1. Introduction:
instructions to contributors notes from the editor
2. Lotus Activities: reports and abstracts
3. Recent Lotus Literature
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P. R. Beuselinck, USDA-ARS
University of Missouri
207 Waters Hall
Columbia, MO 65211 USA
FAX 573-882-1467
Purpose:
The Lotus Newsletter consists of informal
communications of research information on Lotus spp. Reports
of any phase of research on Lotus breeding, genetics, taxonomy,
management, utilization or physiology are welcome. Your biographic
sketches and information about your research objectives, approaches,
and progress including titles of your publications are encouraged.
Seed requests and news items are accepted.
This is the 26th year of publication for the
Lotus Newsletter. Now is the time
to consider contributing to the 27th volume of the Lotus
Newsletter. Contributions generally are compiled without
editing.
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1996 to:
Lotus Newsletter
Dr. P. R. Beuselinck, USDA-ARS
Plant Genetics Research Unit
207 Waters Hall
University of Missouri
Columbia, MO 65211 U.S.A.
E-mail: pbeuselinck@plantsci.missouri.edu
FAX 573-882-1467
The expense of publishing the Lotus Newsletter has been partially covered by unrestricted research support. I will continue to strive for financial support of the Lotus Newsletter to provide you with an unencumbered communication resource. Please note my comments about an internet version of the Lotus Newsletter below.
Many thanks to you who respond to my requests for information about your Lotus research. Your contributions to the Lotus Newsletter help generate a better perspective of the international research and management on the many species of Lotus.
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This was the last issue of the Lotus Newsletter to be printed in a hardcopy form. The cost of printing and mailing has become quite expensive. You should be able to go the Lotus Newsletter homepage and print a copy for yourself or you simply access the homepage and read the volume of your choice without filling your bookshelf. My goal is to work my way back through all the volumes until they are all in electronic format.
From the homepage you should be able to access the current volume or past volumes. The current volume for the year will be a compilation of all Lotus news and articles received between January 1 through December 31.
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If you have not filled-out and sent in a questionnaire in the last two years please complete one. If you know of others interested in the Lotus Newsletter have them submit a questionnaire and they'll be added to the mailing list.
The illustration on the cover is of Lotus conjugatus L. has again been graciously provided by Ana Arambarri (Argentina) . The Lotus illustration is the 4th in a series of illustrations that started with Volume 23.
Stephanie L. Greene,
Curator
USDA, ARS WRPIS
WSU-IAREC
Prosser, WA 99350.
Since its inception, the U.S. Lotus collection has been housed at the Northeast Regional Plant Introduction Station (NERPIS) in Geneva, New York. In February, 1995, the forage crop collections, including Lotus, were transferred from Geneva, NY to the Western Regional Plant Introduction Station (WRPIS) in Pullman, WA. Although seed of the Lotus and perennial Trifolium collections will be housed and distributed from the Pullman, WA facility, the collections will be managed and regenerated in Prosser, WA along with the Medicago collection. Prosser, WA is located in southeastern Washington, an area conducive to forage legume seed production.
Current focus on the collection includes regeneration of accessions designated in the proposed core subset of Lotus corniculatus. Recently collected accessions are being regenerated as resources permit. Collection documentation continues to improve. Climatic data, including monthly precipitation, % cloudiness, air surface temperature and snow coverage; soil type, texture and slope; and ecoregion classification have been obtained from the EPA/NOAA Global Ecosystem Database based on reported and estimated latitude and longitude values of collection sites. Efforts are underway to include this information and additional supplementary passport data into the Germplasm Resources Information Network (GRIN). A new version of PC-GRIN will be distributed as soon as it becomes available.
Requests for seed from the collection, and
copies of PC-GRIN, can be directed to me at Prosser, WA:
Stephanie L. Greene USDA, ARS WRPIS
WSU- Irr. Agric. Res. and Ext. Center Prosser, WA
509-786-9265 (phone)
509-786-9370 (fax)
(internet address): sgreene@ars-grin.gov
G. SéguinSwartz1 and W. F. Grant2
1Agriculture and AgriFood Canada Research Centre, Saskatoon, Saskatchewan S7N 0X2, Canada
2Department
of Plant Science, Macdonald Campus of McGill University, Ste.
Anne de Bellevue, Quebec H9X 3V9, Canada
Attempts have been made to produce haploid plants in L. angustissimus L., L. corniculatus L., L. emeroides Murr., L. halophilus Boiss. & Sprun., 4x L. japonicus (Regel) Larsen and 4x L. tenuis Waldst. & Kit. via anther culture. Multicellular microspores were observed in anthers of L. halophilus cultured on potato medium. Some evidence for androgenesis in L. corniculatus was provided by the observation of haploid cells (dihaploid, 2n = 12) in root tips of a plant regenerated from antherderived callus tissues. Considerable basic research is required in anther and microspore culture of Lotus species.
Plant regeneration of birdsfoot trefoil from callus cultures both through organogenesis (Niizeki and Grant 1971, Swanson and Tomes 1980), somatic embryogenesis (Mariotti et al., 1984; Damiani et al. 1985, 1990) and protoplastderived calli (Ahuja et al. 1983; Niizeki and Saito 1986; Webb et al. 1987; Niizeki 1993; Vessabutr and Grant 1995) has been very successful. It has been stated that Lotus protoplasts show the most prolific regeneration among any forage legume protoplast system (Ahuja et al. 1983). However, attempts to culture anthers and isolated microspores of various species and interspecific hybrids have not been successful in producing androgenic plants (Niizeki and Grant 1971; Niizeki and Kita 1973; Niizeki 1977; Niizeki and Saito 1986). In none of these studies were microspore divisions leading to the formation of multicellular units and embryoids, observed in cultured anthers. Furthermore, the presence of haploid cells was not detected in antherderived callus tissues and all regenerated plants were either tetraploid or octoploid (Niizeki and Grant 1971). A single report of spontaneous haploid parthenogenesis has been reported from a cross between a male sterile plant of L. corniculatus (2n=24) and a plant of L. tenuis (2n = 12) (Negri and Veronesi 1989). The dihaploid plant was diploid (2n 2x= 12) and had the L. tenuis phenotype
This report presents some results from anther culture studies using six tetraploid (natural (L. angustissimus (2n=24), L. corniculatus (2n=24), L. emeroides (2n=28), L. halophilus (2n=28)) or synthetic (4x L. japonicus (2n=24, 4x L. tenuis (2n=24)) Lotus species, two of which (4x L. japonicus, 4x L. tenuis) have not been previously cultured. These Lotus genotypes were used because of the theoretically greater chance of recovering haploid (dihaploid) plants from a tetraploid rather than a diploid species.
Flower buds containing anthers with microspores at the uninucleate stage were excised and surface sterilized according to a standard calcium hypochloride disinfection treatment. Anther culture was attempted on solid potato medium (Anonymous 1976) supplemented with 2 mgl1 2,4dichlorophenoxyacetic acid and 0.5 mgl' kinetin (6furfurylaminopurine); previous experiments had shown that without exogenous growth regulators, anthers shriveled and turned brown. Cultures were incubated at 25°C under continuous illumination. Only anthers with microspores at the early uninucleate stage were used. In addition, two other experiments were carried out to see the effect of culture medium. Anthers of L. corniculatus genotype B259 were cultured on Murashige and Skoog's MS medium (Murashige and Skoog 1962) and anthers of genotype 84N were cultured on Kao's medium (Kao 1977) supplemented with 3% sucrose and 2 mgl benzylaminopurine; incubation was performed in darkness at 23°C.
Microspore embryogenesis in noncallused
anthers was examined after four weeks of incubation using a standard
acetocarmine procedure. Callus tissues on anthers were subcultured
at monthly intervals on solid MS medium supplemented with 3% sucrose,
1 mgl-' kinetin and 0.1 mgl-1 naphthaleneacetic
acid to promote organogenesis; subsultures were incubated under
light at 25°C. Chromosome counts from callus tissues and
regenerated plantlets were determined using standard fixation
and staining schedules (Darlington and La Cour 1976).
RESULTS AND DISCUSSION
In cultured anthers of L. halophilus, microspores with up to five nuclei could be observed; cell walls had not been laid down in these microspores. Bicellular microspores showing two symmetrical cells with equallystained nuclei were observed in the cultures at a very low frequency (ca 0.1% of the total microspore population); microspores with two asymmetrical cells with differentiallystained nuclei were more frequent (ca 2% of the total microspore population). These microspores were morphologically similar to mature pollen grains found in this species, that is, with a crescentshaped, darkiy staining generative nucleus and a round, more diffuse vegetative nucleus. Multicellular units (Fig. 1) were also observed but at a very low frequency. More advanced stages of development were not seen. However, haploid cells were not found in the callus tissues from the cultured anthers. The observations from the L. halophilus cultures indicate that embryoid development had been triggered. L. halophilus is a selfcompatible species which likely produces microspores with a viable genomic constitution in the dihaploid state. One may at present only speculate as to the factors preventing the differentiation of the embryogenic microspores. Further attempts with this species appear to be warranted. In the other five species, cytological studies provided no evidence for the occurrence of embryonic divisions within the microspores or the presence of haploid cells in callus tissues.
An experiment with L. corniculatus genotype B259 was designed to investigate possible inhibitory effects of agar on androgenesis (Kohlenbach and Wernicke 1978). Embryoid induction could not be observed in any of the cultured anthers; profuse callus formation, however, was observed on all solid and liquid media and several callus cell lines were established. Plantlets were regenerated from these cell lines and grown to maturity under greenhouse conditions. One of the regenerants (BFTA9) was derived from a culture on solid medium supplemented with 2 mgl1 benzylaminopurine and 1 mgl-1 indoleacetic acid. When both the regenerant and the donor plant were grown under the same environmental conditions, they differed remarkably from one another. The mother plant possessed weak, prostrate stems with long internodes and light green leaves, whereas the regenerant had robust, erect stems with much shorter internodes and darker leaves. The plants presented some difference in the anthocyanin content of their stems and florets; in BFTA9 a deepred coloration could be observed on the stems, whereas the donor plant had entirely green stems; anthocyanins were also present on the pedicel and the calyx of the florets of the regenerant but were absent in the donor plant. Differences in the degree of pubescence were also evident; for example, few hairs were present on the calyx of the florets of the regenerant, whereas the pubescence was dense on the calyx of the florets of the donor; the margins of most leaflets of the regenerant were ciliate, whereas, in the donor, the margins were glaborous.
An examination of squashed roottip cells from regenerant BFTA9 revealed a mixoploid condition; a small number of haploid (2n=2x=12) and octoploid (2n=8x=48) cells were interspersed with tetraploid cells. The donor plant had an uniform chromosome number of 24. This interesting finding indicates that BFTA9 may have originated from microsporederived callus tissues that underwent polyploidization, a common feature of cultured tissues (Bayliss 1981).
In the course of several experiments with L. corniculatus genotype 84N, one embryolike structure (Fig. 2) was observed emerging through the wall of one anther. When incubated under a 16h photoperiod, the "embryoid" rapidly turned green; a shoot was produced (Fig. 3), but all efforts to induce rooting were unsuccessful; the shoot later degenerated. Chromosome counts obtained from cells in the leaf tips showed the normal number of 24 chromosomes for birdsfoot trefoil. The origin of this plant is unclear, since it could have arisen either from somatic tissues or microspore development with subsequent chromosome doubling. This is the first report of embryogenesis from cultured anthers of Lotus species.
Anther culture in Lotus species has
proven a most difficult enterprise. The most promising avenues
may be with autotetraploid species that are selfcompatible;
the inbreeding depression brought about by total homozygosity
should not be severe enough to prevent embryogenesis or differentiation
of embryoids into plantlets.
REFERENCES
Ahuja, P. S., Hadiuzzaman, S., Davey, M. R. and Cocking, E. C. 1983. Prolific regeneration from protoplastderived tissues of Lotus corniculatus L. (Birdsfoot Trefoil). Plant Cell Rep. 2: 101 104.
Anonymous. 1976. (A sharp increase of the frequency of pollenplantinduction in wheat with potato medium). Acta Genet. Sinica 3: 2531. In Chinese.
Bayliss, M. W. 1981. Chromosome variation in plant tissues in culture. In: I.K. Vasil, ed., Perspectives in plant cell and tissues in culture. Vol. A. Academic Press, N.Y. pp. 113144.
Darlington, C. D. and La Cour, L. F. 1976. The Handling of chromosomes. 6th Ed., Allen and Unwin, London.
Damiani, F., Mariotti, D., Pezzotti, M. and Arcioni, S. 1985. Variation among plants regenerated from tissue culture of Lotus corniculatus L. Z. Pflanzenzucht. 94: 332339.
Damiani, F., Pezzotti M. and Arcioni, S. 1990. Somaclonal variation in Lotus corniculatus L. in relation to plant breeding purposes. Euphytica 46: 3541.
Kao, K. N. 1977. Chromosomal behavior in somatic hybrids of soybeanNicotiana glauca. Mol. Gen. Genet. 150: 225230.
Kohlenbach, H. W. and Wernicke, W. 1978. Investigations on the inhibitory effect of agar and the function of active carbon in anther culture. Z. Pflanzenphysiol. 86: 463472.
Mariotti, D., Pezzotti, M., Falistocco, E. and Arcioni, S. 1984. Plant regeneration from leafderived eallus of Lotus corniculatus cv. Franco. Genet. Agric. 38: 219223.
Murashige, T. and Skoog, F. 1962. A revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiol. Plant. 15: 473497.
Negri, V. and Veronesi, F. 1989. Evidence for the existence of 2n gametes in Lotus tenuis Wald. et Kit. (2n=2x=12): their relevamce in evolution and breeding of Lotus corniculatus L. (2n=4x=24). Theor. Appl. Genet. 78: 400404.
Niizeki, M. 1977. Haploid, polyploid and aneuploid plants from cultured anthers and calluses in species of Nicotiana and forage crops. J. Fac. Agric., Hokkaido Univ. 58: 343466.
Niizeki, M. 1993. Regeneration of plants from protoplasts of Lotus spp. (Birdsfoot Trefoil). In Y.P. S.Bajaj, ed. Biotechnology in Agriculture and Forestry, Vol. 22. Plant protoplasts and genetic engineering III. SpringerVerlag, Berlin, Heidelberg. pp. 6978.
Niizeki, M. and Grant, W. F., 1971. Callus, plantlet formation, and polyploidy from cultured anthers of Lotus and Nicotiana. Can. J. Bot. 49: 20412051.
Niizeki, M. and Kita, F. 1973. Studies on plant cell and tissue culture. 3. In vitro induction of callus from anther culture of forage crops. J. Fac. Agric. Hokkaido Univ. 57: 293300.
Niizeki, M. and Saito, K. 1986. Plant regeneration from protoplasts of birdsfoot trefoil, Lotus corniculatus L. Jpn. J. Breed. 36: 177180.
Swanson, E. B. and Tomes, D. T. 1980. Plant regeneration from cell cultures of Lotus corniculatus and the selection and characterization of 2,4D tolerant cell lines. Can. J. Bot. 58: 12051209.
Vessabutr, S. and Grant, W. F. 1995. Isolation, culture and regeneration of protoplasts from birdsfoot trefoil (Lotus corniculatus). Plant Cell Tiss. Org. Cult. In press.
Webb, K. J., Woodcock, S. and Chamberlain,
D. A. 1987. Plant regeneration from protoplasts
of Trifolium repens and Lotus corniculatus. Plant
Breed. 98: 111118.
Laboratory of Plant Breeding, Faculty of Agriculture
Hirosaki University, Hirosaki, Aomori-Ken 036, Japan
Protoplast fusion has been a practical method
for removing the barriers of incompatibility in sexual crossing
of agriculturally important plant species. On the other hands,
protoplast fusion induces the heteroplasmic state of fusion partners.
Therefore, it may have opportunities for recombinations and/or
rearrangements of cytoplasmic genomes. In the Plant Breeding Laboratory
of Hirosaki University, five asymmetrical somatic hybrid calli
were produced by protoplast fusion in interfamilial combinations
of rice, strain A-58, and soybean,cv.Harosoy (Niizeki and Kita
1981,Niizeki et al. 1985), of rice and birdsfoot trefoil, cv.Viking
(Niizeki et al. 1992a), and of rice and alfalfa, cv.DuPuit and
cv.Rangelander (Niizeki et al. 1992b) and two intergeneric combinations
of soybean and birdsfoot trefoil (Niizeki et al. 1990) and of
birdsfoot trefoil and alfalfa (Niizeki et al. 1989). They had
been reseached for their karyotypes, isozymes, ribulose-1,5-bisphosphate
carboxylase (RuBisCo), and morphological traits. In this study,
interfamilial and intergeneric asymmetrical somatic hybrids were
analyzed for their nuclear DNAs, mitochondrial DNAs (mtDNA) and
chloroplast DNAs (cpDNA) by the Southern hybridization method.
The aim of this study is to obtain fundamental information of
the nature and behavior of their nucleus and organelle DNAs.
I. Analysis of nuclear DNAs
Nuclear DNAs of somatic hybrids were analyzed
with respect to rDNA. In the Southern blots of interfamilial somatic
hybrids, all hybrid cell lines had the identical banding patterns
of leguminous parents except for one hybrid line of rice and soybean.
The deletion of one DNA fragment of soybean was observed in the
hybrid of rice and soybean. In the case of intergeneric hybrids,
the banding patterns of birdsfoot trefoil were detected in all
of the hybrid cell lines of soybean and birdsfoot trefoil. However,
the deletion of one DNA fragment of birdsfoot trefoil and the
addition of one fragment of alfalfa were observed in the somatic
hybrid cell of birdsfoot trefoil and alfalfa(Fig.1,Table1). These
results show that the intergenomic translocation may have occurred
between the chromosomes of somatic hybrids.
II. Analysis of mtDNAs
In the Southern blots of mtDNAs using of three mitochondrial genes as probes, the novel fragments were detected in several cell lines of four somatic hybrids except the hybrid of birdsfoot trefoil and alfalfa. In addition, the presence or deletion of both parental fragments were observed in the mtDNAs of somatic hybrids of rice and soybean and of rice and alfalfa. These results indicate that some kinds of alterations such as intermolecular and/or intramolecular recombinations of mtDNAs occurred in several cell lines of four somatic hybrids.
III. Analysis of cpDNA
In the Southern blots of cpDNAs, the banding
patterns of cell lines of five somatic hybrids were identical
with those of leguminous species cell lines, using of four chloroplast
genomic DNA fragments as probes. No novel fragments were observed
at all. Therefore, it was suggested that the chloroplasts of five
somatic hybrids sorted out unidirectionally, and that any kinds
of recombinations and/or rearrangements of cpDNAs did not occur
in the five somatic hybrids.
From these results, unidirectional nuclear
genome elimination have occurred in the nuclei of five interfamilial
and intergeneric somatic hybrids. However, chromosomal recombinations
may have occurred in the nuclei of somatic hybrids of birdsfoot
trefoil and alfalfa. Some kinds of recombination and/or rearrangement
may have occurred in mtDNAs of four combinations of somatic hybrids,
but alterations of cpDNAs may not have occurred. Therefore, it
will be possible to expect improvement of the nucleous and mitochondria
in these five interfamilial and intergeneric somatic hybrids.
Fig.1. Southern blot of DNAs of a somatic hybrid cell line(H) between birdsfoot trefoil and alfalfa, and its parental birdsfoot trefoil (B)and alfalfa (A) cell lines. Total DNAs of hybrid and parental cell lines were digested by Bam HI and hybridized with rDNA, pRR217. Deletion of birdsfoot trefoil fragment and co-migrated fragment with that of alfalfa are indicated by dot and arrowhead, respectively.
Table 1. Restriction fragment length polymorphism of nuclear DNAs in a somatic hybrid cell line (H) between birdsfoot trefoil and alfalfa, and their parental birdsfoot trefoil(B) and alfalfa(A) proved with pRR217.
| Hybridized | |||
| fragments | |||
| Bam HI | |||
*: Fragment sizes are indicated in kb.
+: Presence of fragment.
REFERENCES
Niizeki, M. and F. Kita 1981. Cell division of rice and soybean
and their fused protoplast. Japan. J. Breed. 31:161-167.
Niizeki, M.,M. Tanaka, S. Akada, A. Hirai and K. Saito 1985. Callus formation of somatic hybridization of rice and soybean and characteristics of the hybrid callus. Japan. J. Genet. 60: 81-92.
Niizeki, M. and K. Saito 1989. Callus formation from protoplast fusion between leguminous species of Medcago sativa and Lotus corniculatus. Japan. J. Breed. 39:373-377.
Niizeki, M., K. Cai, M. Kihara, S. Nakajo and T. Harada 1990. Somatic hybrids between birdsfoot trefoil and soybean. Lotus Newsletter 21:14-17.
Niizeki, M., S. Nakajo and T. Harada 1992a. Somatic cell hybridization in rice and birdsfoot trefoil. Lotus Newsletter 23:18-22.
Niizeki, M., S.Nakajo, R. Ishikawa, T. Harada
and K. Saito 1992b. Behavior of mitochondrial and chloroplast
DNA in somatic hybrid calli between rice and alfalfa. Japan. J.
Breed. 42:803-809.
O.S. Correa, A. Aranda and A.J.Barneix.
Cátedra de Microbiología, Facultad de Agronomía
Buenos Aires, República Argentina.
SUMMARY
Low soil pH limits the legume culture by effects
on the plant, on the bacterium and on nodule formation and function
(Rice et al. 1977). Alfalfa (Medicago sativa) fail to persist
in moderately acid soils. The poor survival and multiplication
of its symbiotic bacteria, Rhizobium meliloti, which has
been reported as the most acid-sensitive of all the root-nodule
bacteria (Brockwell et. al 1991, Pijnenborg et. al 1991), are
the major cause for the poor growth of the plant under acid conditions.
Lotus tenuis is more tolerant to low pH than alfalfa (Miñón
et. al. 1990) and the Rhizobium loti strains show marked
differences in their response to acidity, with strains grown at
pH 4.5 (Wood et. al 1988).
The purpose of this work was determine the
effects of pH on the growth of M. sativa and L. tenuis
uninoculated and inoculated with appropriate rhizobia. Rhizobium
meliloti strains B 58 and B 323 , R. Loti strain LL
56 were obtained from Instituto Nacional de tecnología
Agropecuaria, INTA, Castelar, Argentina, and R. loti strain
NZP 2037 was obtained from Instituto Nacional de Tecnología
de Chascomús, INTECH, Chascomús, Argentina. The
growth in culture media adjusted to pH 4.0, or 7.0. was determinate
by absorbance at 550 nm and viable counts (cfu/ml).
Seeds of L. tenuis cv. Agroverónica
and M. sativa cv. Florida were surface sterilized and germinated
in water agar. Four seedlings were planted in 300 ml pots with
washed sand, and inoculated immediately with approximately 107
cfu of a single strain of Rhizobium, which was previously
grown to turbidity in broth. The pots were maintained in a controlled
environment chamber with 25ºC, 16 h day and 8 h night, and
watered with 1/5 diluted solution Hoagland (1950). The solution
was adjusted before watering to pH 4, 4.5, 5.0, 6.0, 6.5, 7.0
or 8.0 with HCl 0.1 N. In the inoculated treatment, no nitrogen
was added to the rooting solution, in the uninoculated controls
combined N ( KNO3 0.75 g/l ) was added. After 50 days the plants
were removed from the sand and examined for nodules, dried for
48 h at 70°C and weighed. Analysis of variance was performed
on data.
R. meliloti strains
multiplied readily at the high pH value, but multiplication failed
at the low pH value. In contrast, R. loti strains show
no significative differences in growth at both pH. This results
indicate that in liquid culture, loti rhizobia are tolerant
to acidity at least at pH 4.0, whereas meliloti rhizobia
are significantly affected by low pH stress.
The growth of M. sativa plants was
markedly affected by low pH in both conditions of N supply. Total
dry weight for the uninoculated plants provided with mineral N
was highly increased at pH values above 6.0, showing a poor growth
at lower pH values. These results are in disagreement with Rice
et al. (1977), who reported that the alfalfa plant is capable
of successful growth at pH as low as 4.0 when combined nitrogen
is supplied.
For the plants inoculated with their symbiotic
bacteria the growth decreased at pH values bellow 6.0, showing
differences among the two strains, with a poorer growth of the
plants inoculated with the B58 strain. The lost of viability of
R. meliloti at low pH is a major factor contributing to
the poor growth of alfalfa (Rice et al. 1977). Although the ability
of these strains to grow at acid pH in laboratory media, this
doesn't indicate the ability of nodulating at the same pH value.
These results suggest that in M. sativa cv. Florida the
pH below 6.0 affects both the host plant growth and the nodule
development
In contrast, uninoculated L. tenuis
cv. Agroverónica showed no significant difference in its
growth at all pH assayed . Under inoculated conditions, the growth
depended upon the strain used. The plants inoculated with LL 56
almost doubled in growth that inoculated with NZP 2037. LL 56
strain grew at pH 4.0 or 7.0 without appreciable differences,
and in inoculated assays behaved as highly effective.
As a conclusion, in alfalfa-R. meliloti
symbiosis both the plant and the bacteria show a sensitivity to
soil pH. Therefore, efforts to improve yields should be directed
to search strains of R. meliloti with the ability to nodulate
under acid conditions, as well as alfalfa varieties tolerant to
low pH soils. On the other hand, in the L. tenuis-R. loti
symbiosis, both plant and bacteria seem to have developed acid
pH tolerance. According to our results, the infectiveness and
effectiveness of the selected strain would be an important factor
to be considered in this system.
REFERENCES
Brockwell, J., Pilka, A. and Holliday,
R.A. 1991. Australian Journal of Experimental Agriculture
31, 211-219.
Miñón, P.D., Sevilla, G.H.,
Montes, L.P. and Fernandez, O. 1990. Boletín técnico
no98. Unidad Integrada INTA Balcarce. 16 pp.
Pijnenborg, J. W.M., Lie, T.A. and Zehnder,
A.J.B. 1991. Plant and Soil 131, 1-10.
Rice, W.A., Penney, D.C. and Nyborg, M. 1977.
Canadian Journal of Science 57, 197-203.
Wood, M., Cooper, J.E. and Bjourson, A.J.
1988. Plant and Soil 107, 227-231.
Pilar Rubio and Nora
Altier
Instituto Nacional de Investigacion Agropecuaria
INIA La Estanzuela, Proteccion Vegetal
CC 39173, 70000 Colonia, URUGUAY
A survey of fungi associated with seed of
birdsfoot trefoil was done at INIA La Estanzuela Exp. Stn. (National
Institute for Agriculture Research, Uruguay), from October 1994
to May 1995. In order to select the seed health testing methodology,
we compared two incubation methods (water agar plate vs. blotter)
and two seed pretreatments (with or without surface disinfection)
over 10 seed lots. The water agar plate method using seed without
surface disinfection resulted in higher counts of fungi, and was
chosen for further testing. Forty seed lots from the major birdsfoot
trefoil seed production area of Uruguay were evaluated using a
randomized complete block design with four replicates over time.
Incidence, frequency and prevalence were calculated for each identified
fungal genus. Incidence was expressed as percent of seeds with
a genus relative to the total seeds assessed; frequency was expressed
as the ratio between the mean incidence of a genus and the mean
incidence of total fungi; prevalence was expressed as percent
of lots with a genus relative to the total lots assessed. Mean
incidence of total fungi varied significantly (P<0.05) among
seed lots, with an average of 10.7% and a range from 1.7% to 38.2%.
Storage fungi (Aspergillus and Penicillium) averaged
5.1%, seed contaminant fungi (Alternaria tenuis,
Cladosporium, Curvularia, Epicoccum, Helminthosporium, Pithomyces
and Rhizopus) averaged 5.3%, and pathogenic fungi (Colletotrichum,
Fusarium, Leptosphaerulina, Phoma, Rhizoctonia and Stemphylium)
averaged 0.3%. Alternaria was the most frequent genus,
representing 37% of total fungi; it had a mean incidence of 4%
and a prevalence of 100%. In order to evaluate the effect of the
different fungi on seed quality, we determined percentages of
germination (following ISTA methodology) and correlated this variable
with fungal incidence. Percentages of germination varied significantly
(P<0.05) within a range from 59% to 94%. Seed lots with low
germination presented the highest counts of storage fungi and/or
Alternaria. Correlation coefficients between germination
and incidence of total fungi, storage fungi, and contaminants
were r=-0.75, r=-0.69, and r=-0.43, respectively (P<0.05);
correlation coefficient between germination and incidence of pathogenic
fungi was r=-0.10 (NS). The presence of storage fungi and contaminants
contributes to the process of seed deterioration by reducing seed
germination. The presence of pathogenic fungi, despite low percents,
may play an important role as potential source of inoculum for
disease development under field conditions. The impact of fungi
associated with seed of birdsfoot trefoil on the seed quality
and on the crop productivity should be further assessed.
Rossana Jorajuria, Gustavo
Rando, and Nora Altier
Instituto Nacional de Investigacion Agropecuaria
INIA La Estanzuela, Proteccion Vegetal
CC 39173, 70000 Colonia, URUGUAY
Four regions from the major forage legume
seed production area in Uruguay were monitored for fungal leaf
and stem diseases from November 1994 to January 1995. Within each
region, three birdsfoot trefoil and three red clover seed fields
were sampled three times from closing date to harvest, at regular
intervals of 3-4 weeks. One hundred sampling units (stems) were
taken from each field, following a W sampling pattern. Incidence
and severity were assessed separately for leaf and stem diseases,
and causal organisms were isolated and identified. Incidence was
expressed as percent diseased units relative to the total units
assessed. Severity was rated using an 8-class visual scale for
leaf spots (0 = without symptoms; 7 > 50% diseased area) and
a 5- class visual scale for stem spots (0 = without symptoms;
4 > 50% diseased area). For birdsfoot trefoil, leaf spot incidence
varied from 28 to 100% and severity from 0.31 to 4.42; stem spot
incidence varied from 2 to 78% and severity from 0.02 to 1.37.
Stemphylium and Colletotrichum were the most frequently
isolated fungi (94% and 72%) from leaves and stems, respectively.
For red clover, leaf spot incidence varied from 7 to 100% and
severity from 0.07 to 5.29; stem spot incidence varied from 3
to 100% and severity from 0.03 to 3.48. Stemphylium and
Colletotrichum were again the most frequently isolated fungi
(87% and 64%) from leaves and stems, respectively. The widespread
occurrence of leaf and stem fungal diseases in seed fields of
both legumes over different regions supports the potential role
of them limiting seed production. Despite differences among regions
and fields, incidence and severity showed a trend to gradually
increase over successive sampling dates, indicating an association
between days after closing date and disease levels, which should
be studied in more detail. The simultaneous occurrence of several
pathogenic fungi on leaves and stems of both legumes (referred
to as a "disease complex") has important epidemiological
implications, which should be considered when implementing disease
control strategies.
Nora Altier
Instituto Nacional de Investigacion Agropecuaria
INIA La Estanzuela, Proteccion Vegetal
CC 39173, 70000 Colonia, URUGUAY
The following studies are in progress at INIA
La Estanzuela Exp. Stn. (National Institute for Agriculture Research),
Uruguay:
A field survey was initiated in September
1994 at three different locations on 1-, 2-, and 3-year-old birdsfoot
trefoil crops, to evaluate incidence and severity of Fusarium
crown and root disease. Fusarium isolates are being characterized
based on vegetative compatibility (VCG's) using nitrate non-reducing
mutants.
Greenhouse studies were initiated in 1995
to develop a standard test to characterize birdsfoot trefoil for
resistance to Fusarium crown and root disease. One cycle
of selection will be done within an adapted population, and progress
of selection will be assessed.
Soil samples from different crop rotation
systems will be plated on selective culture media to determine
level of inoculum of F. oxysporum, F. solani, and
other Fusarium spp., causal agents of crown and root disease
of birdsfoot trefoil
José L. Remis, Oscar A. Ruíz, Rodolfo
A. Ugalde and Alberto A. Iglesias
Instituto Tecnológico Chascomús
Camino Circunv. Laguna
Km 6. Casilla de Correo 164
Chascomús (7130). Bs. As. Argentina.
ABSTRACT
Lotus spp from an Introduction Garden established in Chascomús,
a typical area of Salado River Basin, are being evaluated since
1994. Results show that of the many species appraised (including
naturalized Lotus tenuis), Lotus corniculatus var.
hirsutus exhibited the higher productivity and nutritional
value. On the other hand, seeds of the different Lotus
species were found to be attacked by Bruchophagus platypterus,
a bug representing a plant pest. Interestingly, Lotus corniculatus
var. hirsutus showed a significant resistance to the bug
infection. As a whole, results indicate the importance of Lotus
corniculatus var. hirsutus for the improvement of pasture
quantity and quality in the geographical area studied.
INTRODUCTION
The so called "Depresion del Rio Salado" (Salado River Basin) extends an about 7,000 km2 region in Buenos Aires Province (Argentina). Soils in this area are characterize by a high salinity and alkalinity, being poorly drained and periodically exposed to waterlogged conditions. The region is mainly utilized for beef and dairy cattle production, with principal feed for these purposes represented by native grassland and naturalized Lotus tenuis (Montes, 1987). All these characteristics determine a high technological delay, with a low productivity result (i.e. beef production of 70 kg of livestock/ha/year) (Bochetto, 1981).
A proposed rational strategy to develop in the region is the introduction of foreign pastures, specially leguminous species, in order to increase the cattle production efficiency. In this way, Lotus spp. represent an important forage legume because of their growing conditions and significant nutritional value. Different experiences have been carried out with Lotus species thriving in Argentina (L. tenuis, L. corniculatus and L. pedunculatus), being L. tenuis a foreign species that naturally spread in the Salado River Basin (Montes, 1980, 1987). However, the use of different Lotus species/varieties has not been explored in an intensive manner and the achievement of a technological answer to the problems of the region is far to be reached.
The "Intituto Tecnologio Chascomús (INTECH)"
, is located in the Salado River Basin, being one of ours efforts
oriented to the study of Lotus spp. in order to obtain
an effective tool to adequately increase the economic efficiency
of the zone. Indeed, we have developed an Introduction Garden
composed of several Lotus species, from which we are evaluating
the behavior of the different species/varieties with respect to
their productive parameters. Aims of the present report are in
two ways: i) to introduce our group and Institute in the field
and the community of Lotus research, and ii) to summarize
experimental data concerning forage disponibility and infection
by plant bug pests, which were obtained with the more representative
(and potentially interesting) species so far studied.
MATERIALS AND METHODS
The Introduction Garden was composed by parcel blocks (1 x 5 m) randomly distributed in an area completely representative of the Salado River Basin. Seeds of the different species/varieties were swollen in water during 2 days, and then germinated and grown in growth chambers with an 18 h photoperiod and 20oC average temperature. Developed plants were rusticated and transplanted to the corresponding parcel block in the Introduction Garden in the fall of 1994 (by the end of March). Samples for analysis started to be monthly taken by May 1994.
Samples were collected manually from a 0.25 m2 frame
in the parcel blocks and the green matter determined as the total
weight of the just cut plant (Jaunarena, 1991). Dry matter was
determined after incubation (until constant weight) in an oven
at 105oC, as previously described (Jaunarena, 1991).
Whole plants, including roots were morphologically examined at
the microscopic level. Seeds were obtained from mature fruits
(manually collected in January and February) and analyzed by microscopy.
The presence of Bruchophagus platypterus in seeds and the
evaluation of the infection was carried out after Mujica (1987).
RESULTS AND DISCUSSION
In the establishment of the Introduction Garden in INTECH we started with a germplasm composed of 70 different Lotus seeds (including 36 species and 6 varieties). From the data obtained at the present time, Table 1 shows the more productive species, and they are compared with naturalized L. tenuis. As shown the productive behavior of L. corniculatus var. alpinus was similar to L. tenuis, whereas L. corniculatus x L. pedunculatus and L. filicaulis exhibited an increased production of dry matter. Interestingly, L. pedunculatus showed a dry matter production 10% higher than the reference L. tenuis, even when the green matter production of the former was comparatively low. These data suggest a potential importance of L. pedunculatus in terms of nutritional value.
The most productive species of those studied in our Introduction Garden resulted L. corniculatus var. hirsutus, which exhibited a significantly higher production of green matter and (more importantly) dry matter than L. tenuis (Table 1). Moreover L. corniculatus var. hirsutus was found to be a good forage for the region considering its adaptation, persistence and nodules formation in roots.
During the analysis of Lotus spp. seeds by microscopy we observed the presence of B. platypterus, a bug previously reported as a pest for L. tenuis plants naturalized in Argentina (Mujica, 1987). Table 2 shows the infection observed in different Lotus species. It can be seen that seeds of L. pedunculatus x L. corniculatus showed a low infection during January but that in February the number of bugs was similar to other Lotus species. It is worth to note the low number of B. platypterus found in seeds of L. corniculatus var. hirsutus, indicating a significant resistance to the infection by this plant variety (Table 2).
Out results suggest that B. platypterus is one important
bug to be considered as a pest of Lotus spp. growth in
the region under study. An interesting behavior was exhibited
by L. pedunculatus, since it exhibited a significant production
of dry matter (with a high dry matter:green matter ratio); and
by L. pedunculatus x L. corniculatus, because of
the relatively low infection by B. platypterus. However,
the species exhibiting the best growth performance in our study
was L. corniculatus var. hirsutus. The high productivity
and nutritional value observed for L. corniculatus var.
hirsutus together with its meaningful withstanding to infection
by B. platypterus, make of this variety a main option to
rationally postulate an improvement of pastures in the region.
In this way, it is tempting to speculate on the possibility of
using L. corniculatus var. hirsutus to obtain hybrid
varieties with productivity and/or resistance to plant pests more
convenient than the currently naturalized L. tenuis species.
Works in our Institute are being continued, looking for a technological
tool for the Improvement of the productivity in the Salado River
Basin.
ACKNOWLEDGMENTS
The authors are greatly indebted to Ana M. Arambarri for generously
providing seeds and helpful initial suggestions. This work was
supported (in part) by BID-CONICET grant No. 0507. OAR, RAU and
AAI are Members of the investigator Career from CONICET.
REFERENCES
Bochetto, R.M. 1981. Incorporation of technology in the argentine livestock sector from an institutional perspective. Ph.D. Thesis, Michigan State University. East Lansing, MI. 246 pp.
Jaunarena, G. 1991. Estimacion de la disponibilidad forrajera. Rev. Crea 1:13-21.
Montes, L. 1980. Narrowleaf trefoil naturalized in low land fields in Buenos Aires Province (Argentina). Lotus Newslett. 11:9
Montes, L. 1987. Current research on Lotus tenuis in Balcarce (Argentina). Lotus Newslett. 18:13.
Mujica, M. 1987. Prescience de Bruchophagus platypterus
en Republica Argentina Infestación de semillas de Lotus
tenuis. Rev. Fac. Argonomia UNLP. 63:82-90.
Table 1. Green matter and dry matter production by Lotus spp. in the Introduction Garden of INTECH.
| Green Matter | Dry Matter | ||
| Species/Varietiey | Origin | (kg/ha/year) | (kg/ha/year) |
| L. corniculatus | Turkey | 5,136 | 1,253 |
| L. corniculatus var. alpinus | Turkey | 5,362 | 1,308 |
| L. corniculatus var. arvensis | France | 4,952 | 1,228 |
| L. corniculatus var. hirsutus | Spain | 6,767 | 1,774 |
| L. corniculatus x L. pedunculatus | New Zealand | 5,678 | 1,420 |
| L. filicaulis | Spain | 5,470 | 1,433 |
| L. parviflorus | Portugal | 4,915 | 1,180 |
| L. pedunculatus | Chile | 4,003 | 1,433 |
| L. rectus | Greece | 3,208 | 853 |
| L. tenuis | Naturalized | 5,552 | 1,305 |
Table 2. Infection of Lotus spp seeds by Bruchophagus platypterus.
| Species/variety | I | II | III | Total | |||||
| Jan | Feb | Jan | Feb | Jan | Feb | ||||
| L. corniculatus var alpinus | 14 | 16 | 0 | 1 | 5 | 12 | 48 | ||
| L. corniculatus var. hirsutus | 0 | 7 | 0 | 0 | 0 | 5 | 12 | ||
| L. corniculatus x L. pedunculatus | 1 | 18 | 0 | 0 | 2 | 4 | 25 | ||
| L. frondosus | 14 | 6 | 2 | 4 | 24 | 14 | 64 | ||
| L. parviflorus | 16 | 11 | 3 | 0 | 12 | 4 | 46 | ||
| L. tenuis | 14 | 19 | 0 | 6 | 0 | 4 | 43 | ||
aNumbers indicate seeds found infected (at the different degree) from a sample of 300 seeds (in each month, January or February) of each species/variety randomly taken from the corresponding parcel block.
bThe different degrees of the infection are defined after Mujica (1987); I. Empty seeds with perforated envelope. II. Seeds containing bug larvae. III. Seeds containing adult bugs.
cTotal number of infected seeds (at any degree) from
a total sample (Jan plus Feb) of 600 seeds.
Liliana Ferrari1
and Irene Pallares2
1Ing. Agr. Laboratorio de Análisis
de Calidad de Semillas
2Lic.Qca. Laboratorio Central
1,2Facultad de Ingeniería y Ciencias Agrarias,
Universidad Nacional de Lomas de Zamora, Ruta. Prov. No4
Km.2 (1832) Lomas de Zamora. CC95, Buenos Aires. Argentina.
Lotus forage
species of major diffusion in the Argentine Republic are Lotus
tenuis and Lotus corniculatus. L. tenuis is naturally
spread in an extensive calving production area of Buenos Aires
province. Each one is adapted to different productive situations.
Their seeds are morphologically very similar.
This makes difficult their identification in a purity analysis
of a sampled seed lot.
SDS-PAGE was applied with the aim of identifying
both species from seed samples.
MATERIALS AND METHODS
Storage proteins were extracted from bulked
ungerminated seed samples of three accessions of Lotus tenuis
and four of Lotus corniculatus. Three g of each sample
were finely ground using a Tecator mill. Portions of 40 and 80
mg. were weighed from each finely ground bulk .Polypropylene hemolysis
tubes were used for extraction of proteins using ISTA method for
peas and ryegrass ( 1992). The ratio of extracting solution was
the indicated by Gardiner and Forde (1992). Two modifications
were made: 1-Immediately after the addition of the extracting
solution all the samples were homogenized with a vortex mixer.
2-The samples of 80 mg were treated with a mechanic homogenizer
with teflon pestle. This was an attempt of improving extraction.
Samples were incubated for one hour. All the extracts were finally
centrifuged in a Sorvall centrifuge, during 20 minutes at 15,000
rpm. Five ml of each supernatant and of the standard were loaded
using a Hamilton syringe in individual wells of minigels. Gel
buffers for main and stacking gels were prepared by ISTA method.
The Mini-Protean II electrophoresis cell and
the Power Pac 300 (Bio-Rad) were successfully used. Standard employed
was Bio-Rad Nro.:161-0317. Tank buffer was Tris-Glycine pH 8.3.
It was used to fill wells, upper and lower reservoirs. Running
conditions were: 200 V (constant voltage setting) and run time
approximately 40 minutes. Gels were fixed, stained and destained
following ISTA (1992). Coomassie Blue (Bio-Rad) was used.
RESULTS AND DISCUSSION
Electrophoregrams showed 23 bands in both
species, varying in position and thickness. Differences among
accessions of each specie were not taken into account. Figure
resumes the bands founded in each specie. Bands were named D1,
D2, ...,D23, considering ìDî as the distance from
the origin. An ascending scale was designed based on the thickness
of bands from T1 to T4.
Although there were differences in presence /absence and thickness of bands, the main distinctions between species were clearly displayed in D7, D8, D9 and D10.
In the cited sequence the schemes were
Lotus corniculatus: T4 - T4 - T2
- T2 and Lotus tenuis: T4 - T2
- T4 - T1.
Lotus corniculatus and
L. tenuis can be identified by SDS- PAGE of storage proteins
from seed sampled lots using the D7...D10
electrophoregram sequence.
REFERENCES
Gardiner, S.E. and Forde, M.B. 1992. Identification of cultivars of grasses and forage legumes by SDS-PAGE of seed proteins. In: Seed Analysis. Linskens, H.F. and Jakson, J.F. Ed. Springer-Verlag. pg. 44-45.
ISTA. International Seed Testing Association. 1992. Handbook of Variety testing. Proposed ISTA standard reference method for the identification of varieties of peas and ryegrass by SDS-PAGE. pg. 2.7-210.
Figure: Electrophoregrams of storage proteins in seed bulks of Lotus tenuis and Lotus corniculatus.
M.P.Robbins, and T.E.Evans
Cell Manipulation Group
Institute of Grassland and Environmental Research
Plas Gogerddan, Aberystwyth, SY23 3EB, UK.
One of the problems of working with transgenic
legumes relates to the storage of a large number of transformed
lines. At IGER we have produced a range of lines co-transformed
with GUS (Webb et al, 1994), antisense DFR (Carron et
al, 1994), antisense chalcone synthase (Colliver et al,
1994) and antisense ENOD2 (Skøt et al, 1996). Our
preferred method for storing L. corniculatus lines transformed
with Agrobacterium rhizogenes is to retain lines at 4oC.
Briefly, 1cm root tips from 'hairy roots'
are grown on 0.8% agar supplemented with 1/2 B5 basal medium together
with 3% sucrose. After 2-3 weeks at 25oC, plates are transferred
to 4oC and then routinely subcultured every 6 months.
However on occasions, stored root cultures can be lost due to
infection, cold room breakdown etc. We present here a simple method
for rescuing valuable root culture lines from derived glasshouse-grown
plants.
MATERIALS AND METHODS
Take young stem or petiole segments, approximately
1cm in length, from glasshouse-grown plants. Decontaminate by
soaking for 10 minutes in 20% sodium hypochlorite. Then wash several
times in sterile distilled and deionised water and discard any
stem sections with excessive bleaching at cut ends.
Place segments on 1/2 B5 plates supplemented
with 3% sucrose but no antibiotics and place in dark at 25oC.
After 2-4 weeks 'hairy roots' should be noted growing from the
ends of the segments and these can then be excised and cultured
as normal 'hairy roots'.
COMMENTS
This method has allowed us to recover Lotus
lines harbouring constructs in binary vectors. We do not know
however whether this procedure promotes the silencing of transgene
expression but this could be easily tested by comparing levels
of antibiotic resistance, kanamycin or hygromycin, in stock root
cultures and in root cultures rescued from derived transgenic
plants.
REFERENCES
Carron TR, Robbins MP, Morris P. Theor. Appl. Genet. 87, 1006-1015 (1994)
Colliver SP, Robbins MP, Morris P. Acta Hort. 381, 148-151 (1994)
Skøt L, Minchin FR, Timms E, Fortune MT, Webb KJ, Gordon AJ. Plant and Soil (submitted)
Webb KJ, Robbins MP, Mizen S. Transgenic Research 3, 232-240 (1994)
Nagy László
Research Institute for Irrigation
Szarvas, Hungary
In Hungary the birdsfoot trefoil has been grown only 70 years,
but alfalfa and red - clover for 200 years.
European demand for seed set the cropping off. At the beginning
there was no cultivar and the seed production was done at territory
under abundant precipitation over high subsoil water. In the beginning
of second world war Hungary was at leading position in respect
of seed export. This time there was one certificated cultivar
namely JAKI.
For the moment four cultivars are available: Orsegi, Szabolcs-1
(Kornelia) G keskenylevelu, and Puszta. The main purpose of production
is unaltered - seed production. The position of seed and forage
yielding territories see on 1st figure, just here can be seen
data on lucerne and red clover too.
As you can see, red clover and birdsfoot trefoil can be grown
successfully under more than 600 mm per year precipitation. Here
there are weakly to strongly acidic soils with low phosphorus
and high aluminum content.
The average cropland and yield data you can see in 1st table.
(The extent of cropland of all the three crops after 1985 decreased
strongly).
I think that considerable fluctuating of seed producing area,
due to altering of export demand and other specific problems such
as sorts mixing, undeveloped populations, lack of proper weed
control, few bees for pollination, high degree of acidity, cultur
weed (Trifolium and Medicago species) infection.
Widely known is the idea that to produce birdsfoot trefoil seeds
in more sure than do alfalfa ones especially became of fewer parasite.
The lower yield fluctuation can be due to lower difference between
maximum and minimum seed and hay yield that achieved in Hungary
in relation the time in question, see 1st table of second part.
1st Table
Data on mean fodder and seed production of M. sativa, T. pratense and L. corniculatus in Hungary (1961-1985)
| Species | Hay | Seed | ||
| Ha | t/ha | Ha | kg/ha | |
| M. sativa true value | 368374 | 4,66 | 39534 | 130,2 |
| 10,4 | 14,2 | 23,3 | 27,5 | |
| T. pratense true value | 74974 | 3,49 | 17182 | 146,8 |
| 26,8 | 14,5 | 46,8 | 18,6 | |
| L. corniculatus true value | 19027 | 2,03 | 3013 | 105,5 |
| 14,1 | 15,9 | 40,5 | 22,9 | |
Marginal values of national yield of fodder crops
(1961-1985)
| Species | Yield Type. | Value | Max | |
| Max | Min. | Min. | ||
| M. sativa | Hay (t/ha) | 5,80 | 2,97 | 1,95 |
| Seed (kg/ha) | 168,0 | 94,8 | 1,78 | |
| T. pratense | Hay (t/ha) | 3,84 | 2,91 | 1,32 |
| Seed (kg/ha) | 172,8 | 111,8 | 1,54 | |
| L. corniculatus | Hay (t/ha) | 2,40 | 1,80 | 1,33 |
| Seed (kg/ha) | 116,8 | 86,4 | 1,35 | |
Parisi L, MM Mujica and MJ
Arturi
Area de Genética y Mejoramiento Animal
y Vegetal
Facultad de Ciencias Agrarias y Forestales
UNLP, CC 31 (1900) La Plata, Argentina
INTRODUCTION
The productivity of some grasslands in the
area called "Pampa Deprimida Bonaerense" in Argentina
can be improved through the incorporation of Lotus tenuis
(Waldst et Kit). Some data indicate the feasibility of its establishment
through the inter-sowing (Miñon et al, 1988; 1990). However,
the low vigor of the seedling affect the success of the inter-sowing.
Seed weight is a trait associated to seedling vigor as it was
found in different populations of L. tenuis (Beuselinck
and McGraw, 1982; Mujica and Rumi, 1991).
The germination speed and their uniformity
are characters that also would condition the establishment and
these could be little or not determined by the seed weight. Furthermore,
the longevity of the seeds is also a character that facilitates
the use of the improved materials. Mujica and Rumi (1991) observed
that seeds of different populations preserved at 5-7 °C maintained
its viability during 6 years.
The objective of this work was to evaluate
the variability in the germination performance and seed longevity
of L. tenuis.
MATERIALS AND METHODS
Seeds of 20 clones produced in polycross among
32 clones with 25 repetitions were used. The harvest and threshing
of the fruits was accomplished manually, in January 1991. The
seeds were maintained in a refrigerator (5-7ºC) until the
experiment began, 47 months after the threshing, therefore being
unnecessary its scarification (Mujica and Rumi 1991). It was determined
the weight of 100 seeds of each clone (average of 4 samples).
These were germinated in 285 x 208 x 25 mm "telgopor"
sandwich boxes on a moist (water saturated) blotting paper. The
experimental unit consisted of 50 seeds, sown in lines. Each box
included 10 treatments (clones) and 2 border lines. It was used
a complete randomized design with 3 repetitions.
Germination tests were performed in the laboratory
with the daily monitoring of the extreme temperatures in a maximum
and minimum thermometer. The extreme minimum and maximum temperatures
recorded during the experiment were 16.5 and 20.5 ºC, respectively.
Each 24 h the number of germinated seeds (radicles 2 mm) was registered,
and simultaneously the seeds were removed from the boxes. The
trial ended 8 days after the sowing. For quantitative analysis
of the germination speed the following index was applied according
with Maguire (1962):
GSI= ( No. of germinated seeds on day 1/1
)+....+ ( No. of germinated seeds on day n /n )
GSI: germination speed index.
n: number of days after sowing.
For daily percentage of germination, accumulative
germination and GSI the analysis of variance of data was performed.
The percentages were transformed into arcsin. Tukey test was used
at the 1% level to compare the treatments. Also the regression
of the GSI on the germination percentage and on the daily accumulative
germination were determined.
The broad-sense heritability (h2b)
of GSI was calculated. The variance of the experimental error
and the variance of the treatments were considered estimates of
the environmental variance (VE) and the genetic variance (VG),
respectively. Therefore h2b= VG /(VG + VE/r)
RESULTS
The analysis of variance of the accumulated
germination for each day after sowing, indicated the existence
of significant differences (P=0,01) among the clones in days 2,
3, 4 and 5.
From day 6 until the end of the experiment (day 8), significant differences (P=0,05) were not found and all the clones reached a high value in the accumulated germination (general mean = 98.146%±1.436). Considering the age of the seeds (47 months), the maintenance of the viability under the conditions described was very acceptable. These results were in agreement to those previously reported for seeds of the same species preserved at low temperature during 3 and 6 years (Mujica and Rumi, 1991). The differences observed among the clones during the first days were reflected in the GSI values, which showed significant differences (P < 0,01; Table 1). The averages of 20 clones were distributed according to:
These differences in the vigor of the seeds
could have existed from the harvest or either could have expressed
at some moment during the conservation stage. If the second alternative
would be true the results would mean the early detection of some
loss of vigor, possibly related with seed longevity.
The regression analyses of the GSI on the
accumulative and daily germination show that GSI was more strongly
determined by the germination on day 2, (Fig 1). This implies
that the germination performance two days after sowing would allow
to evaluate indirectly the speed of the germination.
The value of broad-sense heritability (h2b)
of the GSI was very high (h2b= 0,919). This is due
to the genetic variability available and to the scarce variation
originated by environmental causes.
The correlation coefficient among the germination
speed and the 100-seed weights (r = 0.406) was not significant
at 5% level (r0.05 = 0.444).
Beuselinck and McGraw (1982) determined a
positive and significant correlation (P<0.01) among the weight
of 100 seeds and the total dry weight of the seedling at 2, 4,
and 6 weeks after sowing. Mujica and Rumi (1991) in two populations
of the same species reported similar results. This implies that
the seed weight is a component of seedling vigor. According to
the results of this experiment, the speed of the germination would
not be an important way through which the weight of the seed would
determine the vigor of the seedling.
REFERENCES
Beuselinck PR and RL McGraw (1982). Seedling vigor of three Lotus species. Crop Science, 23: 390-391.
Maguire JD (1962). Speed of germination aid in selection and evaluation for seedling emergence and vigor. Crop Sci. 2: 176-177.
Miñon et al (1990). Lotus tenuis: leguminosa forrajera para la Pampa Deprimida. Boletin técnico no. 98 . ISSN 0522 - 0548. Unidad integrada Balcarce.
Miñon D and Colabelli M (1988). Intersiembra de Lotus tenuis en un pastizal natural de la Pampa Deprimida (Argentina). Resúmenes del XI Congreso Latinoamericano de Producción Animal. La Habana, Cuba:61.
Mujica MM and CP Rumi (1991). Estado de dureza en las semillas de Lotus tenuis: efecto de las condiciones de conservación. Rev. de la Fac de Agr, UNLP, 66/67: 63-66.
Mujica MM and CP Rumi (1991). Estudio de correlaciones
entre posibles componentes del vigor de las pl·ntulas de
Lotus tenuis. I° Simposio del Género Lotus,
1991. INTECH, Chascomús. Libro de resúmenes: 55-56.
Table 1. Analysis of variance for the germination speed index (GSI) values.
| Source of variation | df | Mean square | F-ratio | Sig. level |
| Between clones | 19 | 48.05 | 12.20 | .0000 |
| Within clones | 40 | 3.94 |
X = 29.41
c.v.= 6.74%
Figure 1. Regression of germination speed on the germination two days after sowing.
P. R. Beuselinck1
and J. J. Steiner2
1USDA-ARS,
Plant Genetics Research Unit, Columbia, MO 65211
2USDA-ARS, National Forage Seed Production Research
Center, Corvallis, OR 97331.
'ARS-2620' birdsfoot trefoil (Lotus corniculatus
L.) was released by the USDA-ARS in cooperation with the Missouri
Agricultural Experiment Station in March 1995. ARS-2620 is the
first birdsfoot trefoil cultivar that exhibits rhizomes that may
increase persistence under pasture, range, and other uses.
ARS-2620 was developed from the mating of
five wild germplasm accessions (G31272, G31273, G31276, G31298,
and G31317) from Morocco with ' Norcen' and 'AU Dewey' and germplasm
MU-81. The five Moroccan accessions are unique among L. corniculatus
in that they possess rhizomes. Hybrids were verified using RAPD
analysis. The F1 progeny were field evaluated for rhizome
production, vigor, dry matter production, forage quality, incidence
of Rhizoctonia foliar blight (caused by Rhizoctonia solani
Keuhn), seed production, and winterhardiness. All F1
progeny exhibited the rhizome trait.
Forty-seven F1 progeny were selected
for best combinations of traits and vegetatively-propagated to
produce 25 ramets of each selected progeny. The ramets were transplanted
at Corvallis, OR open-pollinated seed production in isolation.
Equal numbers of seed collected from each plant constituted the
Syn 1 (Breeder) seed lot of ARS-2620.
ARS-2620 is similar to its commercial parents,
Norcen and AU Dewey, but more variable in morphology, like MU-81.
It is semierect, with small- to medium-sized leaves and fine-
to medium-sized stems. It contains a larger number of early-flowering
plants than Norcen or AU Dewey. ARS-2620 easily distinguished
from other cultivars by its rhizomes production. However, the
expression of rhizomes may not be found in every plant of ARS-2620
as rhizome production can be influenced by management practices,
edaphic conditions, and other factors. Development of ARS-2620
was intended for pastures and open range, though it may be useful
for revegetation of disturbed sites such as mine spoils, highway
right-of-ways, and cut-over forests.
Genetic material of this release has been deposited in the National Plant Germplasm System where it is available for research purposes as PI 592503. Exclusive rights for production and marketing of ARS-2620 has been awarded by USDA-ARS on a competitive basis. Protection for ARS-2620 has been sought under the Plant Variety Protection Act of 1994.
J. Stougaard1 and
P. R. Beuselinck2
1Department
of Molecular Biology, Aarhus University, Gustav Wiedsvej 10, DK-8000,
Aarhus C, Denmark
2USDA-ARS, Plant Genetics Research Unit, Columbia,
MO 65211
GIFU B-129-S9 Lotus japonicus (Regel)
Larsen germplasm was released by the USDA-ARS in cooperation with
the Department of Molecular Biology, Aarhus University, Denmark
in April 1995. Handberg and Stougaard (1) reported that L.
japonicus is suitable for genetic and molecular biology research
because: (i) it is a diploid (2n=2x=12), perennial, autogamous
legume with good seed set, and a sexual regeneration time of approximately
3 mo, (ii) it has a relatively small haploid genome size, estimated
at 0.5 pg per haploid complement, and (iii) it is susceptible
to Agrobacterium tumefaciens and transgenic plants can
be regenerated after hygromycin, geneticine, or kanamycin selection.
Stable transformation followed by regeneration has been demonstrated
(1,2). Transformed plants can be generated efficiently and quickly
using GIFU B-129-S9 germplasm.
GIFU B-129-S9 germplasm, was developed from
the 'Gifu' accession B-129 obtained from William F. Grant, McGill
University in Quebec, Canada. The original source of B-129 was
collected near Gifu, Japan, by Professor I. Hirayoshi, of Kyoto
University. An inbred line of B-129 was established from plants
multiplied in pollinator-free growth cabinets. Through the S3
generation, seed of a maximum of 10 plants were bulked. Single-seed-descent
was practiced, starting with the S4 through the S7
. Seed of the S8 and S9 were bulked. The
S9 constitutes the GIFU B-129-S9 germplasm.
The growth form of mature GIFU B-129-S9 plants
is intermediate with multiple branches up to 30 cm long. Flowering
is indeterminate. Plants are cross-fertile making classical genetic
studies possible. Fast-growing strains of Rhizobium loti
and some slow-growing strains of Bradyrhizobium spp. will
nodulate GIFU B-129-S9 germplasm (1), but R. loti strain
NZP 2235 is recommended for fast and effective nodulation.
Seed of this release has been deposited in
the National Plant Germplasm System through the USDA-ARS Regional
Plant Introduction Station, Pullman, WA 99164-6402 where it is
available for research purposes as PI 591056.
REFERENCES
EFFECTS OF COPPER
CONCENTRATION ON MINERAL NUTRIENT UPTAKE AND N OF COPPER-TOLERANT
AND NONTOLERANT LOTUS PURSHIANUS L.
AUTHOR: LIN, S.L.
SOURCE: ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY. (ECOTOXICOL. ENVIRON.
SAF.) NOV 1994. V. 29 (2) P. 214-228.
**************************************
DISSECTING MOLECULAR
MECHANISMS OF NODULATION: TAKING A LEAF FROM ARABIDOPSIS.
AUTHOR: KOLCHINSKY, A.; FUNKE,
R.; GRESSHOFF, F.M.
SOURCE: PLANT MOLECULAR BIOLOGY. (PLANT MOL. BIOL.) OCT 1994.
V. 26 (2) P. 549-552.
**************************************
INTERNAL PHOSPHORUS
REQUIREMENTS OF SIX LEGUMES AND TWO GRASSES.
AUTHOR: PINKERTON, A.; RANDALL,
P. J.
SOURCE: AUSTRALIAN JOURNAL OF EXPERIMENTAL AGRICULTURE:34: 3,
P373-379, 11 REF.; 1994.
TRIFOLIUM BALANSAE AND MEDICAGO MUREX, WITH T.
SUBTERRANEUM FOR COMPARISON, WERE GIVEN 7 RA TES OF P FERTILIZER
(0-128 KG/HA) IN 1991 AND 1992 IN FIELD EXPERIMENTS. T. BALANSAE,
M. MUREX, M. POLYMORPHA, ORNITHOPUS COMPRESSUS, LOTUS PEDUNCULATUS
(L. ULIGINOSUS), PHALARIS AQUATICA AND DANTHONIA
RICHAROSONII WERE GROWN IN SAND CULTURE IN GLASSHOUSE EXPERIMENTS
AND GIVE N NUTRIENT SOLUTIONS CONTAINING 0.05-1.6 MMOL/LITRE.
DIAGNOSTIC INDICES WERE DERIVED FOR BLADES OF THE YOUNGEST OPEN
LEAVES (YOL) OR YOUNGEST EXPANDED BLADES, AND FOR WHOLE SHOOTS.
CRITICAL TOTAL PLANT (PT) CONCENTRATION IN THE YOL OF T. BALANSAE
DID NOT DECLINE UNTIL FULL FLOWERING AND WAS THE MOST STABLE INDICATOR.
THE RANGE OF CRITICAL CONCENTRATIONS WAS 0.45-0.5 O. FOR BOTH
DIAGNOSIS OF DEFICIENCY AND PREDICTION OF SEASONAL YIELD. AN INORGANIC
P (PI) CONCENTRATION OF 150 MG/KG WAS CRITICAL FOR T. BALANSAE
DURING VEGETATIVE GROWTH ONLY. CRITICAL CONCENTRATIONS IN M.
MUREX DECLINED FROM AN EARLY STAGE, BUT A PT CONCENTRATION
IN YOL OF 0.40, WAS THE MOST USEFUL INDICATOR FOR DIAGNOSIS UNTIL
FLOWERING. THE CRITICAL VALUES FOR T. SUBTERRANEUM AGREED
WELL WITH PREVIOUSLY PUBLISHED DATA. CRITICAL P CONCENTRATIONS
IN O. COMPRESSUS WERE SIMILAR AT 2 SAMPLING TIMES. FOR
THE REMAINING SPECIES, CRITICAL CONCENTRATIONS DECLINED WITH TIME
AND IT WAS NECESSARY TO KNOW PLANT AGE WHEN INTERPRETING THEM.
**************************************
NODULATION STUDIES
ON LEGUMES EXOTIC TO AUSTRALIA: SYMBIOTIC RELATIONSHIPS BETWEEN
CHAMAECYTISUS PALMENSIS (TAGASASTE) AND LOTUS
SPP.
AUTHOR: GAULT, R. R.; PILKA,
A.; HEBB, D. M.; BROCKWELL, U.
SOURCE: AUSTRALIAN JOURNAL OF EXPERIMENTAL AGRICULTURE:34: 3,
P385-394, 51 REF.; 1994.
STRAINS OF RHIZOBIUM AND BRADYRHIZOBIUM WERE ISOLATED
FROM SOIL AROUND THE ROOTS OF CHAMAECYTISIS PALMENSIS GROWING
AT 15 WIDELY SEPARATED LOCATIONS IN SE AUSTRALIA. A FURTHER COLLECTION
OF STRAINS OF BOTH RHIZOBIUM LOTI AND BRADYRHIZOBIUM
SP. WAS ASSEMBLED FROM 18 LEGUMES INCLUDING LOTUS SPP.
AND OTHER SPECIES SYMBIOTICALLY RELATED TO LOTUS. THE STRAINS
WERE USED TO INOCULATE C. PALMENSIS AND 4 SPECIES OF LOTUS
IN CONTROLLED EXPERIMENTS. C. PALMENSIS FORMED NODULES
AND FIXED N2 WITH ALL OF ITS HOMOLOGOUS RHIZOBIA BUT THERE WAS
A WIDE RANGE OF EFFECTIVENESS AMONG THE 15 STRAINS. C. PALMENSIS
ALSO FORMED NODULES WITH EACH OF THE L8 STRAINS FROM OTHER SPECIES
BUT FIXED N2 WITH ONLY 10. FOUR SPECIES OF LOTUS WERE INOCULATED
WITH 3 C. PALMENSIS STRAINS. ONE STRAIN NODULATED EACH
SPECIES AND FIXED N2 WITH L. CONIMBRICENSIS AND L. CORNICULATUS
BUT NOT WITH L. PARVIFLORUS OR L. PEDUNCULATUS (L.
ULIGINOSUS). A SECOND C. PALMENSIS STRAIN FORMED NODULES
WITH ALL 4 LOTUS SPP. BUT DID NOT FIX N2, WHILE THE THIRD
NODULATED ONLY L. PEDUNCULATUS BUT DID NOT FIX N2. A PATTERN
ANALYSIS BASED ON THE NODULATING ABILITY OF THE HOST PLANTS IN
ASSOCIATION WITH 21 STRAINS SHOWED THAT C. PALMENSIS AND
L. CORNICULATUS FORMED 1 SYMBIOTIC GROUP, AND THE OTHER
3 LOTUS SPECIES FORMED A THIRD GROUP. THE PATTERN ANALYSIS
PROCEDURE BASED ON NODULATING CAPACITY OF 21 RHIZOBIAL STRAINS
IN ASSOCIATION WITH THE 5 HOST SPECIES INDICATED SUBSTANTIAL SYMBIOTIC
DIVERSITY WITHIN THE COLLECTION, WITH THE STRAINS COMPRISING 8
DIFFERENT SYMBIOTIC GROUPS. NO STRAIN WAS HIGHLY EFFECTIVE ON
BOTH C. PALMENSIS AND ANY OF THE 4 SPECIES OF LOTUS.
DATA WERE INSUFFICIENT TO CLASSIFY THE ROOT-NODULE BACTERIA OF
C. PALMENSIS AS EITHER RHIZOBIUM LOTI OR BRADYRHIZOBIUM
SP.
**************************************
A SURVEY OF PROPORTIONAL
DEPENDENCE OF SUBTERRANEAN CLOVER AND OTHER PASTURE
LEGUMES ON N2 FIXATION IN SOUTH-WEST AUSTRALIA UTILIZING 15N NATURAL
ABUNDANCE. (LANG:EN)
AUTHOR: SANFORD, P.; PATE,
J. S.; UNKOVICH, M. J.
SOURCE: AUSTRALIAN JOURNAL OF AGRICULTURAL RESEARCH:45: 1, P165-181,
46 REF.; 1994.
A SURVEY OF THE SYMBIOTIC PERFORMANCE OF THE LEGUME COMPONENT
OF ANNUAL PASTURES ON 81 FARMS (243 SITES) WAS UNDERTAKEN IN THE
SOUTHERN COASTAL REGION OF WESTERN AUSTRALIA. THE 15N NATURAL
ABUNDANCE TECHNIQUE WAS USED TO DETERMINE THE PERCENTAGE OF PLANT
N DERIVED FROM THE ATMOSPHERE (%NDA) USING ARCTOTHECA CALENOULA
AS THE PRINCIPAL NON-FIXING REFERENCE SPECIES. %NDFA VALUES WERE
THEN RELATED TO EDAPHIC AND MANAGEMENT INFORMATION, E.G. SOIL
TOTAL N. SOIL PH, STOCKING RATES AND CROPPING HISTORY OF THE SITES.
THE PRINCIPAL LEGUME SPECIES ENCOUNTERED EXHIBITED SIMILAR MEAN
%NDFA VALUES BUT SUBSTANTIAL VARIATION IN SYMBIOTIC PERFORMANCE
WAS EVIDENT ACROSS THE SITES: TRIFOLIUM SUBTERRANEUM 72%
NDFA (RANGE 0-100%), MEDICAGO SPP. 71% NDFA (RANGE 7-100%),
LOTUS SPP. 81% NDFA (RANGE 1-100%), ORNITHOPUS COMPRESSUS
76% NDFA (RANGE 25-100%) AND TRIFOLIUM BALANSAE 69% NDFA
(RANGE 0-100%). IN THE CASE OF T. SUBTERRANEUM, THE MOST
WIDELY OCCURRING SPECIES, 29% OF SITES SURVEYED RECORDED %NDFA
VALUES WITHIN THE RANGE 0-65%, SUGGESTING THAT SYMBIOTIC PERFORMANCE
MIGHT WELL BE QUITE WIDELY LIMITING TO HERBAGE PRODUCTION IN THE
STUDY REGION. OF THE 24 EDAPHIC AND MANAGEMENT FACTORS EVALUATES,
ONLY PERCENTAGE AL IN SHOOT DM SHOWED A SIGNIFICANT RELATIONSHIP
WITH NDFA, WITH 40% OF THE PASTURES SURVEYED DEEMED AT RISK IN
TERMS OF ACIDITY RELATED AL TOXICITY. CORRELATIONS OF NDFA WITH
SOIL PH AND SOIL TOTAL N PRODUCED EXAMPLES OF HIGH VALUES %NDFA
FOR T. SUBTERRANEUM BEING ASSOCIATED WITH VERY LOW SOIL
PH OR HIGH SOIL N. SUGGESTING POSSIBLE ADAPTION OF SYMBIOTIC PARTNERSHIPS
TO ACIDITY OR HIGH MINERAL N.
**************************************
DISSECTING MOLECULAR
MECHANISMS OF NODULATION: TAKING A LEAF FROM ARABIDOPSIS.
AUTHOR: KOLCHINSKY, A.; FUNKE,
R.; GRESSHOFF, P. M.
SOURCE: PLANT MOLECULAR BIOLOGY:26: 2, P549-552, 19 REF.; 1994.
APPROACHES TO UNDERSTANDING THE MOLECULAR EVENTS INVOLVED IN NODULATION
ARE BRIEFLY CONSIDERED. TRANSGENIC STUDIES IN LOTUS CORNICULATUS
ARE MENTIONED, AS IS THE PROPOSAL THAT L. JAPONICUS
BE USED AS AN 'ARABIDOPSIS-EQUIVALENT' MODEL SYSTEM FOR NODULATION
RESEARCH. TWO ATTRACTIVE SYSTEMS FOR THE IDENTIFICATION OF HOST
REGULATORY GENES INVOLVED IN NODULATION ARE CITED AS (1) THE POSITIONAL
CLONING OF NODULATION-RELATED GENES IDENTIFIED BY MUTATIONS FROM
AYAC LIBRARY OF SOYABEAN AND 2) TRANSPOSON TAGGING OF THE L.
JAPONICUS GENES.
**************************************
BREEDING OF LEGUMES
FOR USE AS A NITROGEN FIXING CATCH CROP
AUTHOR: RYOBERG, I.
SOURCE: NORDISK OORDBRUGSFORSKNING:76: 3, P8, 1 REF.; 1994.
TO PREVENT NITROGEN LEACHING FROM ARABLE LAND CATCH CROPS CAN
BE USED TO EXTEND PERIODS OF ACTIVE PLANT GROWTH. OUT OF 135 SPECIES,
12 (INCLUDING ANTHYLLIS VULNERARIA, LOTUS CORNICULATUS,
TRIFOLIUM REPENS AND T. PRATENSE) WERE CHOSEN FOR
FURTHER EVALUATION OF THEIR ABILITY TO REDUCE MINERAL N IN THE
SOIL IN FIELD TRIALS DURING 1992-93. COMPARED WITH GRASS SPECIES,
NITROGEN FIXING SPECIES HAD A SIMILAR CAPACITY TO REDUCE SOIL
MINERAL N IN THE AUTUMN BUT IN THE SPRING WERE LESS ABLE TO USE
FREE N IN THE SOIL. CHARACTERS INFLUENCING EFFICIENT USE OF SOIL
N ARE SUGGESTED TO INCLUDE ROOT DEPTH, FROST TOLERANCE AND C/N
QUOTA .
**************************************
EXPRESSION OF GUS
IN PRIMARY TRANSFORMANTS AND SEGREGATION PATTERNS OF GUS, TL-
AND TR-DNA IN THE T1 GENERATION OF HAIRY ROOT TRANSFORMANTS OF
LOTUS CORNICULATUS.
AUTHOR: WEBB, K. J.; ROBBINS,
M. P.; MIZEN, S.
TRANSGENIC RESEARCH:3: 4, P232-240, 22 REF.; 1994.
AGROBACTERIUM RHIZOGENES WAS ASSESSED AS A VEHICLE FOR
TRANSFORMATION OF LOTUS CORNICULATUS. PLANTS WERE CO-TRANSFORMED
USING A. RHIZOGENES STRAIN LBA9402 HARBOURING THE BACTERIAL
PLASMIND PRI1855 AND THE BINARY TRANSFORMATION VECTOR PJIT73.
PRI1855 TRANSFERS BOTH TL AND TR SEOUENCES, WHILE PJIT73 ENCODES
BETA-GLUCURONIDASE (GUS) AND ALSO TWO SELECTABLE MARKER GENES
GIVING RESISTANCE TO THE ANTIBIOTICS KANAMYCIN AND HYGROMYCIN.
THREE PRIMARY TRANSFORMANTS (LINES 1, 6 AND 12) WERE SUBJECTED
TO DETAILED MORPHOLOGICAL AND BIOCHEMICAL ANALYSIS AND LINES 6
AND 12 WERE ALSO ANALYSED BY SOUTHERN BLOTTING. TISSUES OF BOTH
LINES 6 AND 12 WERE RESISTANT TO HYGROMYCIN AND EXPRESSED GUS.
ANALYSIS OF VARIOUS TISSUES OF EACH LINE SHOWED A SIGNIFICANTLY
LOWER GUS ACTIVITY IN LINE 6 THAN IN LINE 12. GENETICAL ANALYSIS
OF PROGENY PRODUCED BETWEEN CONTROL PLANTS AND LINES 6 AND 12
INDICATED THAT LINE 6 HAD ONE DOSE OF THE UID GENE WHILE LINE
12 HAD TWO OR MORE INDEPENDENTLY SEGREGATING DOSES OF THE GENE.
BOTH LINES 6 AND 12 CONTAINED MULTIPLE COPIES OF TL-DNAS WHILE
ONLY LINE 6 WAS TR POSITIVE. IN THE PROGENY OF LINES 6 AND 12
THERE WAS NO EVIDENCE FOR LINKAGE OF TL-DNA WITH UID, WHILE IN
THE PROGENY OF LINE 6, TR-DNA WAS UNDER-REPRESENTED. GUS-POSITIVE
PROGENY WHICH WERE FREE OF BOTH TL AND TR SEQUENCES WERE IDENTIFIED
FROM BOTH LINES.
*
**************************************
A LOTUS JAPONICUS
CDNA ENCODING AN ALPHA SUBUNIT OF A HETEROTRIHERIC G-PROTEIN.
AUTHOR: POULSEN, C.; MAI, X.H.
; BORG, S.
SOURCE: PLANT PHYSIOLOGY. (PLANT PHYSIOL.) AUG 1994. V. 105 (4)
P. 1453-1454.
**************************************
CAN GLUTAMINE SYNTHETASE
ACTIVITY LEVELS BE MODULATED IN TRANSGENIC PLANTS BY THE USE OF
RECOMBINANT DNA TECHNOLOGY?
AUTHOR: TEMPLE, S.J.; BAGGA. S.; SENGUPTA-GOPALAN, C.
SOURCE: TRANSACTIONS. (BIOCHEM. SOC. TRANS.) NOV 1994. V. 22 (4)
P. 915-920.
**************************************
INCREASED ROOT GROWTH
IN ELEVATED CO2: A BIOPHYSICAL ANALYSIS OF ROOT CELL ELONGATION.
AUTHOR. FERRIS, R.; TAYLOR, G.
SOURCE: JOURNAL OF EXPERIMENTAL BOTANY. (J. EXP. BOT.) NOV 1994.
V. 45 (280) P. 1603-1612.
A BIOPHYSICAL ANALYSIS OF ROOT EXPANSION WAS CONDUCTED IN FOUR
CHALK DOWNLAND HERBS (SANGUISORBA MINOR SCOP., LOTUS
CORNICULATUS L., ANTHYLLIS VULNERARIA L. AND PLANTAGO
MEDIA L.) EXPOSED TO EITHER AMBIENT OR ELEVATED CO2 IN CONTROLLED
ENVIRONMENT CABINETS. MEASUREMENTS OF FINE (F) AND EXTRA-FINE
(EF) ROOT EXTENSION RATE (RER), WATER RELATIONS, AND CELL WALL
TENSIOMETRIC EXTENSIBILITY REVEALED DIFFERENCES IN THE DIURNAL
PATTERN OF ROOT GROWTH BETWEEN SPECIES. AFTER 35 D OF EXPOSURE
TO ELEVATED CO2, RER OF BOTH F AND EF ROOTS INCREASED SIGNIFICANTLY
IN DARKNESS AND ON ILLUMINATION FOR S. MINOR, WHILST FOR
A. VULNERARIA (EF ROOTS ONLY) AND L. CORNICULATUS A SIGNIFICANT
INCREASE OCCURRED AT NIGHT WHEREAS FOR P. MEDIA A SIGNIFICANT
INCREASE OCCURRED DURING THE DAY. CELLS MEASURED IN THE ZONE OF
ELONGATION WERE LONGER IN ALL SPECIES EXPOSED TO ELEVATED CO2.
WATER POTENTIAL (PSI(S)), SOLUTE POTENTIAL (PSI), TURGOR PRESSURE
(P), YIELD TURGOR (Y) AND EFFECTIVE TURGOR (PE) WERE MEASURE D
BY STRESS-RELAXATION OF EXCISED ROOT TIPS PLACED IN PSYCHROMETERS.
SOLUTE POTENTIALS DECREASED SIGNIFICANTLY FOR ALL SPECIES FOLLOWING
EXPOSURE TO ELEVATED CO2. IN S. MINOR AND L. CORNICULATUS,
P AND PE, RESPECTIVELY, WERE HIGHER IN ELEVATED CO2. NO SIGNIFICANT
EFFECTS OF CO2ON Y WERE OBSERVED (NOT SHOWN). ROOT CELL WALL TENSIOMETRIC
EXTENSIBILITY, MEASURED AS % PLASTICITY, INCREASED IN ALL SPECIES
EXPOSED TO ELEVATED CO2. THESE RESULTS SUGGEST THAT ROOT GROWTH
IS ENHANCED FOLLOWING INCREASED CELL EXPANSION AND THAT INCREASED
P AND CELL WALL TENSIOMETRIC EXTENSIBILITY ARE BOTH IMPORTANT
FOR ROOT GROWTH IN ELEVATED CO2.
**************************************
ELEVATED CO2 AND
PLANT GROWTH: CELLULAR MECHANISMS AND RESPONSES OF WHOLE PLANTS.
TAYLOR, G.; RANASINGHE, S.; BOSAC,
C.; GARDNER, S.D.L.; FERRIS, R.
SOURCE: JOURNAL OF EXPERIMENTAL BOTANY. (J. EXP. BOT.) NOV 1994.
V. 45 (280) P. 1761-1774. IN THE SPECIAL ISSUE: GROWTH IN PLANTA
/ EDITED BY T.L. WANG, W.J. DAVIES, AND C.J. POLLOCK . PROCEEDINGS
OF A MEETING HELD APRIL 11-15, 1994, SWANSEA, UK.
MUCH RESEARCH HAS FOCUSED ON THE PHOTOSYNTHETIC RESPONSES OF PLANTS
TG ELEVATED CO2, WITH LESS ATTENTION GIVEN TO THE POST-PHOTOSYNTHETIC
EVENTS WHICH MAY LEAD TO CHANGES IN THE GROWTH OF TISSUES, ORGANS
AND WHOLE PLANTS. THE AIM OF THIS REVIEW IS TO IDENTIFY HOW PLANT
GROWTH IS ALTERED IN ELEVATED CO2 AND TO DETERMINE WHICH GROWTH
PROCESSES OR CELLULAR MECHANISMS ARE SENSITIVE TO CARBON SUPPLY.
FOR LEAVES, BOTH THE EXPANSION OF INDIVIDUAL LEAVES AND THE INITIATION
OF LEAF PRIMORDIA ARE STIMULATED IN ELEVATED CO2. WHEN LAMINA
GROWTH IS PROMOTED, THIS IS USUALLY ASSOCIATED WITH INCREASED
LEAF CELL EXPANSION RATHER THAN INCREASED LEAF CELL PROOUCTION.
USING SEVERAL CLONES OF HYBRID POPLAR (POPULUS EURAMERICANA,
P. INTERAMERICANA) TWO NATIVE HERBS (PLANTAGO MEDIA,
SANGUISORBA MINOR) AND BEAN (PHASEOLUS VULGARIS)
WE HAVE IDENTIFIED THE MECHANISM THROUGH WHICH LEAF CELL EXPANSION
IS PROMOTED IN ELEVATED CO2. CHANGES IN THE WATER RELATIONS, TURGOR
PRESSURE (A) AND YIELD TURGOR (Y) OF GROWING LEAVES CANNOT EXPLAIN
INCREASED CELL EXPANSION; THIS APPEARS TO OCCUR BECAUSE CELL WALL
LOOSENING IS PROMOTED, AS SUGGESTED BY THREE PIECES OF EVIDENCE.
(I) THE RATE OF DECLINE OF WATER POTENTIAL WITH TIME IS ACCELERATED
WHEN GROWING LEAVES ARE PLACED IN PSYCHROMETERS AND ALLOWED TO
RELAX, (II) INSTRON-MEASURED CELL WALL EXTENSIBILITY (WEX), IS
GREATER FOR LEAVES EXPOSED TO ELEVATED CO2 AND (III) THE ACTIVITY
OF THE PUTATIVE WALL LOOSENING ENZYME, XET IS INCREASED FOR LEAVES
OF P. VULGARIS EXPOSED TO ELEVATED CO2. SPECIES DIFFERENCES,
HOWEVER, EXIST; IN THE HERB LOTUS CORNICULATUS SMALL STIMULATIONS
OF LEAF GROWTH IN ELEVATED CO2 ARE DUE TO INCREASED LEAF CELL
PRODUCTION AND DECREASED CELL SIZE IN ELEVATED CO2. THESE RESULTS
ARE DISCUSSED IN RELATION TO THE CONCEPT OF FUNCTIONAL TYPES.
THERE IS EVIDENCE TO SUGGEST THAT BOTH CELL PRODUCTION AND CELL
EXPANSION ARE PROMOTED IN ROOTS OF PLANTS EXPOSED TO ELEVATED
CO2. FOR NATIVE HERBS (ANTHYLLIS VULNERARIA, LOTUS CORNICULATUS,
P. MEDIA AND S. MINOR), INCREASED ROOT GROWTH IN
ELEVATED CO2 IS DUE TO INCREASED CELL ELONGATION. IN CONTRAST
TO LEAVES, THIS APPEARS TO OCCUR BECAUSE BOTH ROOT CELL TURGOR
PRESSURE (P) AND ROOT CELL WALL EXTENSIBILITY (WEX ) ARE PROMOTED
BY EXPOSURE OF SHOOTS TO ELEVATED CO2. IN LONGER-TERM STUDIES
ON ROOT GROWTH, THE EFFECTS OF ADDITIONAL CARBON ON THE PRODUCTION
OF ROOT PRIMORDIA AND ROOT BRANCHING ARE OF OVERRIDING IMPORTANCE,
SUGGESTING THAT CARBON SUPPLY MAY INFLUENCE SOME ASPECT OF THE
CELL CYCLE, WHEN EFFECTS ON THE EXTENSION OF INDIVIDUAL ROOTS
MAY NOT BE APPARENT.
**************************************
THE KEEL COLOUR
POLYMORPHISM IN LOTUS CORNICULATUS L.: DIFFERENCES
IN INTERNAL FLOWER TEMPERATURES.
AUTHOR: JEWELL, J.; MCKEE,
J.; RICHARDS, A. U.
SOURCE: NEW PHYTOLOGIST:128: 2, P363-368, 14 REF.; 1994.
KEEL OF FLOWERS OF L. CORNICULATUS WERE CONSISTENTLY HIGHER
IN DARK-KEELED THAN IN LIGHT-KEELED INDIVIDUALS. TEMPERATURE DIFFERENCES
MAY INCREASE WITH HIGHER AMBIENT TEMPERATURES AND AVERAGED 5.7DEGC
AT 23.2DEG AMBIENT. IN OVERCAST CONDITIONS, NO SIGNIFICANT TEMPERATURE
DIFFERENCES BETWEEN DARK-KEELED AND LIGHT-KEELED FLOWERS WERE
OBSERVED, OR LIGHT KEEL TEMPERATURES WERE SLIGHTLY GREATER. IN
GENERAL, TEMPERATURES WITHIN KEELS WERE LOWER THAN AMBIENT. WITHIN
SITES, DARK-KEELED PLANTS SHOWED A TENDENCY TO INHABIT COLDER
MICROSITES THAN DID LIGHT-KEELED PLANTS. CONTRARY TO SOME EARLIER
REPORTS, IT IS SUGGESTED THAT MOST CLINAL VARIATION FOR KEEL COLOR
IS TEMPERATURE RELATED. IT IS SUGGESTED THAT THERE MAY BE AN OPTIMUM
TEMPERATURE FOR POLLEN GERMINATION AND POLLEN TUBE GROWTH. IN
COLD MICROSITES, DARK-KEELED PLANTS WOULD BE MORE FECUND, BUT
IN WARM MICROSITES LIGHT-KEELED PLANTS WOULD SET MORE SEED, THUS
MAINTAINING THE POLYMORPHISM FOUND IN MOIST SITES.
**************************************
CRANBERRY YIELD
AND FRUIT QUALITY REDUCTION CAUSED BY WEED COMPETITION.
AUTHOR: PATTEN, K. D.; WANG, J.
SOURCE: HORTSCIENCE:29: 10, P1127-1130, 17 REF.; 1994.
IN FIELD TRIALS CONDUCTED IN LONG BEACH DURING 1991-92, THE RELATIONSHIPS
BETWEEN CANOPY DENSITY OF THREE PERENNIAL WEED SPECIES (POTENTILLA
PACIFICA, ASTER SUBSPICATUS AND LOTUS CORNICULATUS)
AND CRANBERRY (VACCINIUN MACROCARPON) CV. MCFARLIN AND
STEVENS YIELD AND FRUIT QUALITY WERE EVALUATED. YIELD WAS MORE
SEVERELY AFFECTED BY WEED INTERFERENCES THAN FRUIT SIZE OR COLOR.
BEST-FIT REGRESSION EQUATIONS FOR THE EFFECTS OF WEED DENSITY
ON YIELD, FRUIT SIZ E AND COLOR WERE LINEAR OR QUADRATIC POLYNOMIALS
WITH A STRONG LINEAR COMPONENT. FOR EACH BOG, THE SLOPE OF THE
LINEAR RELATIONSHIP BETWEEN YIELD AND WEED DENSITY WAS MORE NEGATIVE
AS THE MEAN YIELD OF WEED-FREE CONTROLS INCREASED. IN THE STEVENS
CULTIVAR, FRUIT SIZE AND YIELD WERE MORE SENSITIVE AND FRUIT COLOR
WAS LESS SENSITIVE TO CHANGES IN P. PACIFICA POPULATION
DENSITY THAN THOSE OF THE MCFARLIN CULTIVAR.
**************************************
EFFECT OF IMAZETHAPYR
ON LEGUMES AND THE EFFECT OF LEGUMES ON WEEDS.
AUTHOR: WILSON, R. G.
SOURCE: WEED TECHNOLOGY:8: 3, P536-540, 16 REF.; 1994.
A THREE-YEAR EXPERIMENT WAS CONDUCTED NEAR SCOTTSBLUFF, NE, TO
EVALUATE THE SELECTIVITY OF POST-APPLIED IMAZETHAPYR FOR WEED
CONTROL IN ALFALFA (LUCERNE), BIRDSFOOT TREFOIL (LOTUS CORNICULATUS),
CICER MILKVETCH (ASTRAGALUS CICER), RED CLOVER (TRIFOLIUM
PRATENSE), SAINFOIN (ONOBRYCHIS VICIAEFOLIA (O.
VICIIFOLIA)), AND YELLOW SWEETCLOVER (MELILOTUS OFFICINALIS).
IMAZETHAPYR INJURED ALL LEGUMES 15 DAT. IMAZETHAPYR ALSO REDUCED
THE HEIGHT OF BIRDSFOOT TREFOIL , CICER MILKVETCH, RED CLOVER,
AND YELLOW SWEETCLOVER 28 DAT. LEGUME FIRST CUTTING FIELD WERE
NOT REDUCED BY IMAZETHAPYR, AND WITH ALFALFA, BIRDSFOOT TREFOIL,
CICER MILKVETCH, AND SAINFOIN, FIRST CUTTING YIELDS WERE INCREASED
BY IMAZETHAPYR. IMAZETHAPYR REDUCED WEED BIOMASS IN ALL LEGUME
SEEDINGS. WEED BIOMASS IN NEW SEEDLINGS OF ALFALFA WAS REDUCED
MORE THAN THAT OF THE OTHER LEGUMES.;
**************************************
THE EXPRESSION OF
A CHIMERIC PHASEOLUS VULGARIS NODULIN 30-GUS
GENE IS RESTRICTED TO THE RHIZOBIALLY INFECTED CELLS IN TRANSGENIC
LOTUS CORNICULATUS NODULES.
AUTHOR: CARSOLIO, C.; CAMPOS,
F.; SANCHEZ, F.; ROCHA-SOSA, M.
SOURCE: PLANT MOLECULAR BIOLOGY. (PLANT MOL. BIOL.) DEC 1994.
V. 26 (6) P. 1995-2001.
IN PHASEOLUS VULGARIS THERE IS A NODULIN FAMILY, NPV30,
OF CA. 30 KDA, AS DETECTED IN AN IN VITRO TRANSLATION ASSAY. WE
ISOLATED A GENE (NPV30-1) FOR ONE OF THE MEMBERS OF THIS FAMILY.
THE NUCLEOTIDE SEQUENCE OF THE PROMOTER OF NPV30-1 CONTAINS NODULE-SPE
CIFIC MOTIFS COMMON TO OTHER LATE NODULIN GENES. THE PROMOTER
WAS FUSED TO THE GUS REPORTER GENE; THIS CHIMERIC FUSION WAS INTRODUCED
INTO LOTUS CORNICULATUS VIA AGROBACTERIUM RHIZOGENES
TRANSFORMATION. GUS ACTIVITY WAS ONLY DETECTED IN THE INFECTED
CELLS OF THE NODULES OF TRANSGENIC PLANTS. BY CONTRAST, THE EXPRESSION
OF A 35S-GUS CONSTRUCT WAS RESTRICTED TO THE UNINFECTED CELLS
AND THE VASCULAR TISSUE.
**************************************
ANALYSIS OF THE
LUPIN NODULIN-45 PROMOTER: CONSERVED REGULATORY SEQUENCES ARE
IMPORTANT FOR PROMOTER ACTIVITY.
AUTHOR: MACKNIGHT, R.C.; REYNOLDS,
P. H.S.; FARNDEN, K.J.F.
SOURCE: PLANT MOLECULAR BIOLOGY. (PLANT MOL. BIOL.) FEB 1995.
V. 27 (3) P 457-466.
THE PROMOTER FROM THE LUPINUS ANGUSTIFOLIUS LATE NODULIN
GENE, NODULIN45, HAS BEEN ANALYSED TO IDENTIFY CIS-ELEMENTS AND
TRANS-ACTING FACTORS. VARIOUS REGIONS OF THE NODULIN-45 PROMOTER,
FUSED TO THE LUCIFERASE REPORTER GENE, WERE INTRODUCED INTO LOTUS
ROOTS USING AN AGROBACTERIUM RHIZOGENES TRANSFORMATION PROCEDURE.
THE TRANSGENIC ROOTS WERE THEN NODULATED. THE PROMOTER REGION
A (-172 TO +13, RELATIVE TO THE TRANSCRIPTION START SITE) WAS
CAPABLE OF DIRECTING LOW-LEVEL EXPRESSION OF THE REPORTER GENE
AND IN A NODULE-ENHANCED MANNER WHEN COMPARED TO ROOTS. THE ADDITION
OF REGION C (-676 TO -345) RESULTED IN A SIGNIFICANT INCREASE
IN THE EXPRESSION WITHIN THE NODULE, WHILST A LOW LEVEL OF ROOT
EXPRESSION WAS MAINTAINED. THE C REGION, WHICH CONFERS THIS HIGH-LEVEL
NODULE EXPRESSION, CONTAINS THE NODULE CONSENSUS MOTIFS AAAGAT
AND CTCTT. WHEN REGION C WAS LIGATED TO A MINIMAL PROMOTER ELEMENT
FROM THE UNRELATED ASPARAGINASE GENE RATHER THAN THE NODULIN-45
A REGION, NODULE-ENHANCED EXPRESSION WAS STILL APPARENT, BUT AT
A MUCH LOWER LEVEL. MUTATION OF THE AAAGAT ELEMENT IN THIS CONSTRUCT
RESULTED IN A FURTHER SIGNIFICANT DECREASE OF EXPRESSION. GEL
RETARDATION ASSAYS REVEALED THAT A FACTOR FROM LUPIN NODULE NUCLEAR
EXTRACTS INTERACTED WITH TWO SEQUENCE S OF THE C REGION. THE BINDING
OF THE FACTOR TO BOTH OF THESE REGIONS COULD BE REMOVED BY THE
ADDITION OF AN OLIGONUCLEDTIDE CONTAINING THE AT-RICH BINDING
SITE FOR THE SOYBEAN FACTOR NAT2. THIS SUGGESTS THAT THE LUPIN
FACTOR IDENTIFIED HERE IS A NAT2 HOMOLOGUE. NO FACTOR BINDING
WAS OBSERVED TO THE AAAGAT OR CTCTT ELEMENTS PRESENT IN THE C
REGION.
**************************************
IDENTIFICATION OF
SEVERAL SOYBEAN CYTOSOLIC GLUTAMINE SYNTHETASE TRANSCRIPTS HIGHLY
OR SPECIFICALLY EXPRESSED IN NODULES: EXPRESSION STUDIES USING
ONE OF THE CORRESPONDING GENES IN TRANSGENIC LOTUS CORNICULATUS.
AUTHOR: MARSOLIER, M.C.; DEBROSSES,
G.; HIREL, B.
SOURCE: PLANT MOLECULAR BIOLOGY. (PLANT MOL. BIOL.) UAN 1995.
V. 27 (1) P. 1-15.
A DNA FRAGMENT CONTAINING SEQUENCES HYBRIDIZING TO THE 5' REGION
OF GS1 5, A GENE ENCODING SOYBEAN CYTOSOLIC GLUTAMINE SYNTHETASE,
WAS ISOLATED FROM A SOYBEAN GENOMIC LIBRARY. MAPPING AND PARTIAL
SEQUENCE ANALYSIS OF THE GENOMIC CLONE REVEALED THAT IT ENCODES
A CYTOSOLIC GS GENE, GS21, WHICH IS DIFFERENT FROM GS15. IN PARALLEL,
A NUMBER OF CDNA CLONES ENCODING CYTOSOLIC GS WERE ISOLATED USING
THE CODING REGION OF PGS20 AS A PROSE (PGS20 IS A CDNA CLONE WHICH
CORRESPONDS TO A TRANSCRIPT OF THE GS15 GENE). TWO NEW FULL-LENGTH
CDNAS DESIGNATED PGS34 AND PGS38 WERE ISOLATED AND SEQUENCED.
IN THE 5' NON-CODING REGION A STRONG HOMOLOGY WAS FOUND BETWEEN
THE TWO CLONES AND THE GS21 GENE. HOWEVER, NONE OF THESE SEQUENCES
WERE IDENTICAL, WHICH SUGGESTS THAT THERE ARE AT LEAST THREE MEMBERS
IN THIS GROUP OF GENES. IN ORDER TO DETERMINE THEIR RELATIVE LEVELS
OF TRANSCRIPTION, SPECIFIC SEQUENCES FROM PGS34, PGS38 AND GS21
WERE USED IN AN RNASE PROTECTION ASSAY. THIS EXPERIMENT CLEARLY
SHOWED THAT GS21 AND THE GENE ENCODING PGS38 ARE SPECIFICALLY
EXPRESSED IN YOUNG OR MATURE NODULES, WHEREAS THE GENE ENCODING
PGS34 IS HIGHLY TRANSCRIBED IN NODULES AND CONSTITUTIVELY EXPRESSED
AT A LOWER LEVEL IN OTHER SOYBEAN ORGANS. IN ORDER TO FURTHER
ANALYSE THE MOLECULAR MECHANISMS CONTROLLING GS21 TRANSCRIPTION,
DIFFERENT FRAGMENTS OF THE PROMOTER REGION WERE FUSED TO THE ESCHERICHIA
COLI REPORTER GENE ENCODING BETA-GLUCURONIDASE (GUST AND THE
CONSTRUCTS WERE INTRODUCED INTO LOTUS CORNICULATUS VIA
AGROBACTERIUM RHIZOGENES-MEDIATED TRANSFORMATION. ANALYSIS
OF GUS ACTIVITY SHOWED THAT THE GS21 PROMOTER-GUS CONSTRUCTS WERE
EXPRESSED IN THE VASCULATURE OF ALL VEGETATIVE ORGANS. THIS RESULT
IS DISCUSSED IN RELATION TO SPECIES-SPECIFIC METABOLIC AND DEVELOPMENTAL
CHARACTERISTICS OF SOYBEAN AND LOTUS.
**********************************
SYMBIOTIC AND NONSYMBIOTIC
HEMOGLOBULIN GENES OF CASUARINA GLAUCA.
AUTHOR: JACOBSON-LYON, K.;
DENNIS, E.S.; JENSEN, E.O.; JORGENSEN, J.E.; MARCKER, K.A.; PEACOCK,
W.J.
SOURCE: THE PLANT CELL. (PLANT CELL) FEB 1995. V. 7 (2) P. 213-223.
CASUARINA GLAUCA HAS A GENE ENCODING HEMOGLOBIN (CASHB-NONSYM).
THIS GENE IS EXPRESSED IN A NUMBER OF PLANT TISSUES. CASUARINA
ALSO HAS A SECOND FAMILY OF HEMOGLOBIN GENES (CASHB-SYM) EXPRESSED
AT A HIGH LEVEL IN THE NODULES THAT CASUARINA FORMS IN A NITROGEN-FIXING
SYMBIOSIS WITH THE ACTINOMYCETE FRANKIA. BOTH THE NONSYMBIOTIC
AND SYMBIOTIC GENES RETAINED THEIR SPECIFIC PATTERNS OF EXPRESSION
WHEN INTRODUCED INTO THE LEGUME LOTUS CORNICULATUS. WE
INTERPRET THIS FINDING TO MEAN THAT THE CONTROLS OF EXPRESSION
OF THE SYMBIOTIC GENE IN CASUARINA MUST BE SIMILAR TO THE
CONTROLS OF EXPRESSION OF THE LEGHEMOGLOBIN GENES THAT OPERATE
IN NODULES FORMED DURING THE INTERACTION BETWEEN RHIZOBIA AND
LEGUMES. DELETION ANALYSES OF THE PROMOTERS OF THE CASUARINA SYMBIOTIC
GENES DELINEATED A REGION THAT CONTAINS NODULIN MOTIFS IDENTIFIED
IN LEGUMES; THIS REGION IS CRITICAL FOR THE CONTROLLED EXPRESSION
OF THE CASUARINA GENE. THE FINDING THAT THE NONSYMBIOTIC
CASUARINA GENE IS ALSO CORRECTLY EXPRESSED IN L. CORNICULATUS
SUGGESTS TO US THAT A COMPARABLE NONSYMBIOTIC HEMOGLOBIN GENE
WILL BE FOUND IN LEGUME SPECIES.
**************************************
STRUCTURAL IDENTIFICATION
OF THE LIPO-CHITIN OLIGOSACCHARIDE NODULATION SIGNALS OF RHIZOBIUM
LOTI.
AUTHOR: LOPEZ-LARA, I.M.; BERG,
J.D.J. VAN.; THOMAS-OATES, J.E.; GLUSHKA, J.; LUGTENBERG, B.J.J.;
SPAINK, H.P.
SOURCE: MOLECULAR MICROBIOLOGY. (MOL. MICROBIOL.) FEB 1995. V.
15 (4) P. 627-638.
RHIZOBIUM LOTI IS A FAST-GROWING RHIZOBIUM SPECIES THAT
HAS BEEN DESCRIBED AS A MICROSYMBIONT OF PLANTS OF THE GENUS LOTUS.
NODULATION STUDIES SHOW THAT LOTUS PLANTS ARE NODULATED BY R.
LOTI, BUT NOT BY MOST OTHER RHIZOBIUM STRAINS, INDICATING
THAT R. LOTI PRODUCES SPECIFIC LIPO-CHITIN OLIGOSACCHARIDES
(LCOS) WHICH ARE NECESSARY FOR THE NODULATION OF LOTUS
PLANTS. THE LCOS PRODUCED BY FIVE DIFFERENT RHIZOBIUM LOTI
STRAINS HAVE BEEN PURIFIED AND WERE SHOWN TO BE N-ACETYLGLUCOSAMINE
PENTASACCHARIDES OF WHICH THE NON-REDUCING RESIDUE IS N-METHYLATED
AND N-ACYLATED WITH CIS-VACCENIC ACID (C18:1) OR STEARIC ACID
(C18:0) AND CARRIES A CARBAMOYL GROUP. IN ONE R. LOTI STRAIN,
NZP2037, AN ADDITIONAL CARBAMOYL GROUP IS PRESENT ON THE NON-REDUCING
TERMINAL RESIDUE. THE MAJOR CLASS OF LCO MOLECULES IS SUBSTITUTED
ON THE REDUCING TERMINAL RESIDUE WITH 4-O-ACETYLFUCOSE. ADDITION
OF LCOS TO THE ROOTS OF LOTUS PLANTS RESULTS IN ABUNDANT
DISTORTION, SWELLING AND BRANCHING OF THE ROOT HAIRS, WHEREAS
SPOT INOCULATION LEADS TO THE FORMATION OF NODULE PRIMORDIA.
*********************************
IDENTIFICATION OF
SEVERAL SOYBEAN CYTOSOLIC GLUTAMINE SYNTHETASE TRANSCRIPTS HIGHLY
OR SPECIFICALLY EXPRESSED IN NODULES: EXPRESSION STUDIES USING
ONE OF THE CORRESPONDING GENES IN TRANSGENIC LOTUS CORNICULATUS.
AUTHOR: MARSOLIER, M. C.; DEBROSSES,
G.; HIREL, B.
SOURCE: PLANT MOLECULAR BIOLOGY:27: 1, P1-15, 50 REF.; 1995.
A DNA FRAGMENT CONTAINING SEQUENCES HYBRIDIZING TO THE 5' REGION
OF GS15, A GENE ENCODING SOYABEAN CYTOSOLIC GLUTAMINE SYNTHETASE
(GLUTAMATE-AMMONIA LIGASE), WAS ISOLATED FROM A SOYABEAN GENOMIC
LIBRARY. MAPPING AND PARTIAL SEQUENCE ANALYSIS OF THE GENOMIC
CLONE REVEALED THAT IT ENCODES A CYTOSOLIC GS GENE, GS21, WHICH
IS DIFFERENT FROM GS15. IN ADDITION, A NUMBER OF CDNA CLONES ENCODING
CYTOSOLIC GS WERE ISOLATED USING THE CODING REGION OF PGS20 AS
A PROBE (PGS20 IS A CDNA CLONE WHICH CORRESPONDS TO A TRANSCRIPT
OF THE GS15 GENE). TWO NEW FULL-LENGTH CDNAS DESIGNATED PGS34
AND PGS38 WERE ISOLATED AND SEQUENCED. IN THE 5' NON-CODING REGION
A STRONG HOMOLOGY WAS FOUND BETWEEN THE TWO CLONES AND THE GS21
GENE. HOWEVER, NONE OF THESE SEQUENCES WERE IDENTICAL, WHICH SUGGESTS
THAT THERE ARE AT LEAST THREE MEMBERS IN THIS GROUP OF GENES.
IN ORDER TO DETERMINE THEIR RELATIVE LEVELS OF TRANSCRIPTION,
SPECIFIC SEQUENCES FROM PGS34, PGS38 AND GS21 WERE USED IN AN
RNASE PROTECTION ASSAY. THIS EXPERIMENT CLEARLY SHOWED THAT GS21
AND THE GENE ENCODING PGS38 ARE SPEC
