Progress 10/01/09 to 09/30/14
Outputs
Target Audience: Growers and processors in Montana, North Dakota, South Dakota, Idaho, Washington, and Canada. Legume geneticists worldwide. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Several undergraduates and two graduates students obtained training in the laboratory. How have the results been disseminated to communities of interest? Results are presented yearly to growers and industry representatives at various meetings. Results are also presented to colleagues at national and international meetings. Major results are published in international journals. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Under goal (1) we released two high-amylose dry pea varieties, Amigo and B10-10. The latter has been licensed to a private company and will be used for generation of a flour which, because of the slow digestibility of the starch, is suitable for products directed toward the needs of individuals with Type 2 diabetes. We have developed a third line with higher amylose content and higher yields that we expect to release this coming spring. A fourth set of lines that are resistant to powdery mildew require another year of yield trials, but at least one should be ready for release in spring 2016. We continue to investigate the genes in pea that influence stem strength and should complete a QTL study in 2015. Breeding results with the a2 mutant have revealed that this mutation hasdetrimentalpleiotropic effects on yield and stem strength, and we have ceased working with this gene. We have not made any advances on fodder type peas. Under goal (2), the a2 and er1 genes were identified in other laboratories, although the primers reported for er1 have not worked in our hands. We have developed markers tightly linked to En (published), Fw (submitted) and er1 (in use). We have also identified a candidate gene for Fw (unpublished). For goal (3) we ran into complications correlating the original colonies containing theBAC clones with the clones isolated from these colonies. As a result, we did not pursue the construction of an ordered BAC library. The recent release of the Cicer genomic sequence and the current sequencing of the pea and lentil genomes relegate the construction of an ordered BAC library to low priority. However, we have been able to map several hundred STS markers on the pea genome (published and unpublished, have identified the coding sequence for Ser (presented at meetings), have identified candidate genes for wel and Np, and are pursuing the fine mapping of Pu, Pur, Dpo, v, p, n and bulf. The genes st and b were identified by others. With respect to goal (4), several laboratories, including mine, have presented comparisions of conservation of synteny among the cool season legume genomes. We focused on pea linkage group III and identified numerous minorinversions, deletions, and translocations between this linkage group and its homologs in Medicago truncatula. We did not pursue goal (5), as we could not obtain the desired mutant from Novosibirsk.
Publications
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Progress 01/01/13 to 09/30/13
Outputs
Target Audience: The target audience included researchers working in the field of legume genetics, students in genetics and agriculture, seed companies involved in the sale of peas and lentils, cool season legume growers (particularly in the U.S. and Canada), and individuals suffering from type 2 diabetes. Changes/Problems: Several of the genewe had originally proposed to investigate have been identified by others (e.g. a2, st, apu, and b). Our gene tagging and identification efforts now focus primarily on En, Fw, Dpo, and Np, although we are also pursuing the three genes involved in snap pea production (p, v, and n). The a2 mutation appears to have significant negative impact on plant vigor, and we are no longer attempting to develop varieties possessing this gene. We have not been able to obtain funding for constructing an ordered BAC library for Linkage Group III, and with the initiation of a pea genome sequencing project in Canada and France, we are not sure just how to best contribute to this effort. It may be that an ordered BAC library would be an inefficient use of resources. What opportunities for training and professional development has the project provided? I have had five undergraduate and two graduate students work on various aspects of the project in this reporting period. Two of the undergraduate students and both graduate students have been includedas co-authors onpapers or presentations. The modular nature of the projectencourages student participation on specific aspectswith the expectation of the completion of something publishable. How have the results been disseminated to communities of interest? Results are published in scientificjournals and trade publications, presented at scientific meetings, and presented to grower groups and seed companies. What do you plan to do during the next reporting period to accomplish the goals? In the next year we expect to identify one or moremildew resistant, yellow, high-amylose dry pea suitable for release once additional yield trials are performed. Wewill continue to fine mapEn, Fw and the remaing two QTL for fusarium root rot tolerance. QTL affecting stem strength will be mapped in a large F5 populationalong with fine-mapping the position of Np, also segregating in this population.
Impacts
What was accomplished under these goals?
Yellow, high-amylose dry peas suitable for production of flour with a very low glycemic index are being developed. We released MSUPBLB1010 in January, 2013. This line was licensed to a seed company that is now increasing seed stocks for commercial release. This line is susceptible to powdery mildew, and we are now developing lines that have mildew resistance. We are also developing later maturing lines suitable for areas with a longer growing season and lines with less tendency to shatter and with better stem strength. We have identified the coding sequence for Ser and expect to submit our findings for publication this year. We reported a tightly linked marker to En and have identified a second marker tightly linked to Fw. We have identified gene responsible for one of the three QTL contributing to fusarium root rot tolerance in the most tolerant pea lines and intend to submit a manuscript presenting these finding this spring.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Jain, S., Weeden, N., Porter, L., Eigenbrode, S., and McPhee, K. 2013. Finding linked markers to En for efficient selection of Pea Enation Mosaic Virus resistance in pea. Crop Sci. 53:2392-2399.
Weeden, N.F. 2012. A pod splitting mutation on linkage group III. Pisum Genetics 44:1-3. (Appeared in print in 2013)
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Progress 01/01/12 to 12/31/12
Outputs
OUTPUTS: The focus of my work this year has been the development of high-amylose peas and the fine-mapping or identification of important genes in this species. I released a novel high-amylose yellow pea, B10-10, this spring for flour production suitable for people with Type II diabetes. The variety has been licensed and should be in commercial production in a year or so. Investigations into the mechanisms of pod dehiscence revealed a new mutation in pea that dehisces by a different mechanism than the wild pea. Study of this mutant may lead to pea varieties that are less likely to shatter during harvest. I published a detailed list of intron-targeted DNA markers for pea linkage group III, and these markers permit convenient mapping of genes on this linkage group with a precision of within 1 centiMorgan. The list has already been used to identify markers tightly linked to two disease resistance genes (see below). PARTICIPANTS: P. Biswas, who was senior author on the Bulf mapping paper, was a Biotechnology student at Montana State University. She graduated in 2012. Dr. K. McPhee and Dr. S. Jain (both from North Dakota State), and Dr. L. Porter (USDA, Prosser WA) collaborated on the disease resistance genes. Dr. Chengci Chen and Dr. David Sands, both at Montana State University, collaborated on the release of B10-10. TARGET AUDIENCES: Growers in the Northern Plains are interested in the high-amylose pea varieties because these varieties should command a premium price. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
In collaboration with colleagues in North Dakota and Washington I have identified DNA markers very tightly linked to two disease resistance genes in pea: En, which confers resistance to pea enation mosaic virus, and Fw, which confers resistance to race 1 of Fusarium wilt. A manuscript describing the En markers has been submitted for publication and one describing the Fw marker is in preparation. Both of these resistance genes are on linkage group III of pea. The position of a third gene on this linkage group, Bulf, was published this year. Finally, the gene responsible for the leaflet serrations observed in pea lines from Ethiopia was identified as a homolog of NO APICAL MERISTEM. A manuscript detailing this finding is in preparation.
Publications
- Biswas, P. and Weeden, N.F. 2012. The position of Bulf on Linkage Group III. Pisum Genetics 44:6-10. Weeden, N.F. 2012. A pod splitting mutation on linkage group III. Pisum Genetics 44:30-33. Weeden, N.F. 2012. Intron-targeted markers on LGIII polymorphic in the JI1794 X Slow recombinant inbred population. Pisum Genetics 44:36-42.
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Progress 01/01/11 to 12/31/11
Outputs
OUTPUTS: Made selections at row plot stage for improved performance of high-amylose green and yellow dry peas. Entered high-amylose green and yellow dry peas in regional yield trials. Several high-amylose yellow dry pea selections performed very well at Bozeman, although not as well in central and eastern Montana. This pattern paralleled that of Delta, one of the low-amylose lines in the pedigree of several high-amylose lines. As Delta is a popular commercial variety, we decided to release one of the best performing high-amylose lines, B10-10, in January, 2012 as the first high-amylose yellow dry pea for the northern Great Plains. Chengci Chen and Kevin McPhee performed some of the yield trials and row plots in Montana and North Dakota, respectively. Chengci Chen distributed results of the yield trials to growers and other interested parties in presentations at annual grower meetings and as a printed report. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: The results of yield trials and the announcement of the proposed release of B10-10 have been distributed to grower organizations in Washington, Idaho, Montana, and North Dakota. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The development of high-amylose dry pea lines remains the primary focus of the breeding program. High-amylose starch is digested more slowly in the human gut and consumption of food high in this starch greatly moderates the post-prandial blood sugar increase. Thus type 2 diabetics and others desiring to avoid high blood glucose levels often demand foods with a low glycemic index such as those containing high-amylose starches. This last year we concentrated on developing a high-amylose yellow dry pea that can be used in flour blends both to reduce the glycemic index of the flour and to reduce or eliminate the amount of gluten (for individuals with celiac disease). B10-10 was shown to yield nearly as well as the best yielding commercial variety (Delta) we grew in Bozeman. Delta was not the best yielding variety at Moccasin (central Montana) or Richland (eastern Montana), but B10-10 continued to perform almost as well as Delta at both these sites. With the release of B10-10, growers in the Northern Plains now have a good yielding high-amylose yellow dry pea that can be marketed as a flour supplement. We are also interested in incorporating powdery mildew resistance into high-amylose lines and developed another DNA marker for the Er1 locus in pea, which is the primary locus controlling powdery mildew resistance in this crop. In the summer of 2011 another two groups reported the actual identity of the Er1 gene, and we are now using sequences derived from this gene to tag resistance in our breeding lines. Finally, a long term parallel objective to this project has been developing an understanding of the relationships among cultivated legumes. Delgado-Salinas et al present our results of a detailed phylogenic study of the American species that were previously all included in the genus Vigna.
Publications
- Delgado-Salinas, A, Thulin, M., Pasquet, R. Weeden, N., Lavin, M. 2011. Vigna (Leguminosae) sensu lato: The names and identities of the American segregate genera. Amer. J. Bot. 98:1694-1715. Tonguc, M. and Weeden, N.F. 2010. Identification and mapping of molecular markers linked to er1 gene in pea. Plant Mol. Biol. Biotechnol. 1:1-5.
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Progress 01/01/10 to 12/31/10
Outputs
OUTPUTS: Made selections at row plot stage for improved performance of high-amylose green and yellow dry peas. Entered high-amylose green dry peas in regional yield trials. Determined that high-amylose lines are more susceptible to damping off than low-amylose lines. Determined that genistein and methyl jasmonate have a different and inhibitory effect on nodulation in peas than reported in beans. Continued fine-mapping of several genes on chromosome 3 in pea and lentil PARTICIPANTS: Chengci Chen and Karnes Neill performed the regional yield trials. Kevin McPhee and Grant Jackson also grew some of my lines in North Dakota and northwestern Montana, respectively. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The development of high-amylose dry pea lines remains the primary focus of the breeding program. High-amylose starch is digested more slowly in the human gut and consumption of food high in this starch greatly moderates the post-prandial blood sugar increase. Thus type 2 diabetics and others desiring to avoid high blood glucose levels often demand foods with a low glycemic index such as those containing high-amylose starches. Row plots of a number of promising lines were grown at several field research centers in Montana and selections were made yield testing in 2011. We are now concentrating on developing a high-amylose yellow dry pea that can be used in flour blends both to reduce the glycemic index of the flour and to reduce or eliminate the amount of gluten (for individuals with celiac disease). One line, B10-10, appeared to be particularly robust both in terms of habit and yield, and we have increased seed of this line for entry into regional yield trials. Both high-amylose green dry pea lines that we entered in the 2010 regional yield trials performed well, although they were not in the top 20% of the entries in terms of yield (all other entries in the yield trials were low-amylose lines). Field observations in previous years suggested an increased susceptibility of the high-amylose lines to damping off. In 2010 we planted both high- and low-amylose lines in fields known to contain Pythium. Seed treated with metalaxyl as well as untreated seed were planted. The metalaxyl treated seed (both high- and low-amylose) established well. Untreated seed showed poorer establishment, with the low-amylose lines displaying 10-20% mortality and the high-amylose lines 40-70% mortality. We are therefore recommending that seed of high-amylose lines always be treated with a fungicide before planting. Nodulation efficiency in peas was examined using two compounds (genistein and methyl jasmonate) that have been shown to promote nodulation in common bean (Phaseolus vulgaris) in cool soils. We determined that instead of increasing the efficiency of nodulation, the presence of these compounds inhibited nodulation in pea, and we are not recommending their use for peas. Comparison of the gene order in pea, lentil and barrel medic (Medicago truncatula) continues with a particular emphasis on the chromosome 3 homology group. Numerous small deletions, duplications and inversions have been identified, but the barrel medic genomic sequence has provided an good model for identifying markers in specific regions of the respective pea and lentil chromosomes. We have been able to identify co-segregating sequence-tagged markers for several important genes on this chromosome.
Publications
- Chen, D.Z., Chen, C., and Weeden, N.F. 2010. Genistein and mentyl jasmonate inhibit nodulation of Pisum sativum. Pisum Genetics (in press).
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Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: The comparison of pea and lentil linkage groups III with the homologous chromosome in Medicago trucatula (chromosome 3) continued, using genes identified on the medicago genome sequence 2.0 and 3.0 when it was released in October, 2009. The positions on this linkage group of chromosomal breakpoints within Lens and within Pisum were also mapped. The position of two of these breakpoints (one within Pisum sativum and one between Lens culinaris and Lens ervoides) proved to be indistinguishable from one end of the medicago chromosome, suggesting that this may be a fragile site that rearranges in many cool season legumes. Markers have been identified close to the gene (En) conferring resistance to pea enation mosaic virus, including one that has yet to show recombination with this gene (less than 1 cM resolution in our mapping population). Seed of the high-amylose green dry pea, Amigo, was increased as part of the Foundation Seed program in 2009 and will be available to growers in limited amounts for 2010. Additional high-amylose green dry pea lines with better stem strength and powdery mildew resistance have been developed and will be evaluated in yield trials this summer. PARTICIPANTS: H. Randhawa was an undergraduate student working in my laboratory. I am collaboration with Dr. Lyndon Porter and Dr. Richard Larsen, ARS plant pathologists at Prosser, WA for the enation virus screening. TARGET AUDIENCES: For the development of high-amylose dry pea varieties, the primary target audience are the growers in Montana and North Dakota. Growers in other adjacent states might also be considered a secondary audience. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Our comparison of the pea, lentil and medicago linkage groups indicate that within conserved regions, the gene order is nearly identical at 1 centiMorgan resolution. Thus, the pea or lentil breeder/geneticist can predict gene location, identify marker sequences and find candidate genes relatively easily. We demonstrated this fact by walking down the pea linkage group to within 1 cM of the gene En and identifying approximately 10 candidate genes in this region. The marker has allowed the introgression of En into non-resistant lines to become routine and more accurate than direct screening techniques. A high-amylose dry pea ('Amigo') is now available to growers in the Northern Plains.
Publications
- Randhawa, H. and Weeden, N.F. 2009. Refinement of the position of En on LG III and identification of closely linked DNA markers. Pisum Genetics 41:33-35.
- Liew, L.C., Hecht, V., Weeden, N.F., Weller, J.L. 2009. Isolation of Pseudo Response Regulator genes and evaluation as candidate genes for photoperiod response loci. Pisum Genetics 41:19-22.
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: The focus of the project this year was a continued development of sequence tagged site (STS) markers in pea and lentil with a particular emphasis on linkage group III in both crops. In pea, several important genes are located on this chromosome, including En, (conferring resistance to pea enation mosaic virus), Fw (conferring resistance to race of of fusarium wilt), a2 (an alternative white-flower gene that is generally not used in pea breeding) and dpo (the primary gene controlling pod dehiscence). We were able to identify coding sequences tightly linked to two of these genes and published results on the marker and map location of a2. A second manuscript detailing our progress mapping and tagging En is in preparation (Kaur and Weeden, in prep). The release of the high amylose dry pea variety Amigo was approved by the state Variety Release Committee and was subjected to another year of performance evaluations and seed increase. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: The target audience for the STS work are legume geneticists and breeders. These individuals are reached through publications in journals and a conferences. The target audience for the high-amylose dry pea are the growers in the Northern Great Plains. These individuals attend annual field days at research stations and can observed the yield trials at these facilities. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The tagging of a2 and En will make pea breeding programs more efficient and facilitate the use of the a2 mutation. The phenotype of a2 is virtually identical to that of a, and without a marker for each gene is is impossible to select for a2 in a background in which a is segregating. As nearly all commercial pea varieties grown for human consumption possess the a mutation, the replacement of a with a2 in new varieties will permit an increase in genetic diversity and potentially reduce the vulnerability of the crop to certain pathogens. The high-amylose dry pea Amigo is the first such pea available. It has potential due to its slow release of glucose during digestion as a significant part of the diet for those individuals suffering from type II diabetes. The data indicate that there is not a yield penalty associated with the high amylose trait and that such lines perform well in Montana.
Publications
- Weeden, N.F. 2008. A DNA marker and refined map position for A2. Pisum Genetics 40:30-32.
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: Research performed in this project led to the understanding that Mendel's cotyledon color gene, one of those he used to demonstrate that characteristics are inherited as distinct units that appear in the progeny in predictable ratios, is orthologous to the staygreen mutation in meadow fescue (Festuca pratensis), Lolium and in soybean (Glycine max). Additional comparative genetic studies of the domestication process in common bean and garden pea showed that for several traits modified in parallel ways during domestication, the actual genes involved were different. In particular, seed dormancy, dehiscent pods and plant height were clearly controlled by different gene products in the two crops. A BAC library for pea was constructed and partially characterized. Several genes involved in the nitrogen fixation process and associations with rhizobium and mycorrhizal fungi were more precisely mapped and characterized.
PARTICIPANTS: Important collaborators include: Dr. Clarice Coyne, USDA-ARS, WRPIS, 59 Johnson Hall, Washington State University, Pullman, WA. Dr. Kevin McPhee, USDA, Department of Agronomy, 303 Johnson Hall, Washington State University, Pullman, WA. Dr. Alex Y. Borisov, Research Institute for Agricultural Microbiology, Podbelsky Shosse 3, St. Petersburg, Russia Mr. Matthew D. Moffet, Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT.
Impacts
Both the study of Mendel's green cotyledon gene and that of domestication in legumes reveal the power of comparative approaches in genetics. Several attempts have been made to identify and clone the green cotyledon gene in pea, but because it appears to be a transcription factor with an uncertain target it turned out to be extremely difficult to find in pea until orthologous genes had been identified in other species. The results in the domestication analysis indicate that there are many different ways to reach a desired phenotype (e.g. indehiscent pods), suggesting that breeders may have more flexibility than previously recognized. The work on symbiosis genes in pea represents a further advance in our knowledge regarding this very important attribute of legumes. Finally, the construction and partial characterization of a pea BAC library is an important first step in the attainment of a genomic sequence for this organism. Most of the sequence information will come from
the genomic model legume, Medicago truncatula, but the availability of an ordered BAC library a complementary tool that will greatly assist the application of the medicago sequence to practical applications in pea.
Publications
- Armstead, I., I. Donnison, S. Aubry, J. Harper, S. Hortensteiner, C. James, J. Mani, M. Moffet, H. Ougham, L. Roberts, A. Thomas, N. Weeden, H. Thomas and I. King. 2007. Cross-species identification of Mendels I locus. Science 315:73.
- Borisov, A. Yu., T.N. Danilova, T.A. Koroleva, E.V. Kuznetsova, L. Madsen, M. Moffet, T.S. Naumkina, T.A. Nemankin, E.S. Ovchinnikova, Z.B. Pavlova, N.E. Petrova, A.G. Pinaev, S. Radutoiu, S.M. Rozov, T.S. Rychagova, O. Yu. Shtark, I.I. Solovov, J. Stougaard, I.A. Tikhonovich, A.F. Topunov, V.E. Tsyganov, A.G. Vasil'chikov, V.A. Voroshilova, N.F. Weeden, A.I. Zhernakov, V.A. Zhukov. 2007. Regulatory genes of garden pea (Pisum sativum L.) controlling the development of nitrogen-fixing nodules and arbuscular mycorrhiza: A review of basic and applied aspects. Appl. Biochem. Microbiol. 43:237-243.
- Coyne, CJ. M.T. McClendon, J.G. Walling, G.M. Timmerman-Vaughan, S. Murray, K. Meksem, D.A Lightfoot, J. Shultz, K.E. Keller, R.R. Martin, D.A. Inglis, P.N. Rajesh, K.E. McPhee, N.F. Weeden, M.A. Grusak, E.W. Storlie. 2007 Construction and characterization of two bacterial artificial chromosome libraries of pea (Pisum sativum L.) for the isolation of economically important genes. Genome 50:871-875.
- Weeden, N.F. 2007. Genetic changes accompanying the domestication of Pisum sativum L.: is there a common genetic basis to the domestication syndrome for legumes? Ann. Bot. 100:1017-1025.
- Zhukov, V.A. E.V. Kuzetsova, E.S. Ovchinnikova, T.S. Rychagova, V.S. Titov, A.G. Pinaev, A.Y. Borisov, M. Moffet, C. Domoney, T.H.N. Ellis, P Ratet, N.F. Weeden and I.A. Tikhonovich. 2007. Gene-based markers of pea linkage group V for mapping genes related to symbioses. Pisum Genetics 39:19-25.
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Progress 01/01/06 to 12/31/06
Outputs
Using a comparitive genomic approach we identified the ortholog in rice (Oryza sativa) for the staygreen mutation in meadow fescue (Festuca pratensis). This gene also appears to be an ortholog of the staygreen mutation in Lolium and in soybean (Glycine max). Although the manuscript will not appear until January of 2007, we have shown that the same gene is responsible for one of mutations Mendel examined in his pioneering gene studies in the 1860s. DeMason and Weeden (2006) represents another study of a gene family, the Argonaute genes, that might have been responsible for several important mutations in pea. In this case the cloning and mapping of two members of this family indicated that these two genes were not responsible for the variation in leaf morphology in pea that appeared to be similar to mutations in Arabidopsis that were controlled by members of this gene family. Finally, two testa pigmentation mutations in pea, long thought to be controlled by different
loci, were shown to be either controlled by the same locus or by two loci so tightly linked that recombination between them is a very rare event. The erroneous belief that the two mutations were encoded by loci 10 to 20 cM apart was shown to be caused by incomplete penetrance of the U phenotype.
Impacts
The comparative mapping of the staygreen mutation in several crops demonstrates the power of comparative genetics, particularly in using model systems such as rice and Medicago truncatula to reveal the gene responsible for important mutations in other, non-model crops. The study of the Argonaute genes in pea provided two additional DNA markers that can be used to orient the pea map with those of Medicago, Lotus and Phaseolus. The study of testa pigmentation in pea simply cleans up a long-standing error in the literature that was causing problems in the comparison of gene order among studies in pea. It further demonstrated that the U mutation was inappropriate to be used as a standard marker in pea because of its incomplete penetrance.
Publications
- Armstead, I., I. Donnison, S. Aubry, J. Harper, S. Hortensteiner, C. James, J. Mani, M. Moffet, H. Ougham, L. Roberts, A. Thomas, N. Weeden, H. Thomas and I. King. 2006. From crop to model to crop: identifying the genetic basis of the staygreen mutation in the Lolium/Festuca forage and amenity grasses. New Phytol. 172:592-597.
- DeMason, D.A. and N.F. Weeden. 2006. Two Argonaute1 genes from pea. Pisum Genetics 38:3-9.
- Weeden, N.F. 2006. Fs and U appear to be alleles of a locus near the end of linkage group V. Pisum Genetics 38:35-38.
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Progress 01/01/05 to 12/31/05
Outputs
Identification of the genes controlling morphological mutants in pea represented a significant portion of the work published this year. Bai et al. examined the expression and map location of PsPK2, a PINOID-like gene that was a candidate gene for several leaf morphology mutants in pea. However, unlike its counterpart in Arabidopsis, mutations in this gene did not appear to affect leaf development, although promoter sequence analysis did reveal auxin and gibberellin response elements. The green/yellow cotyledon color gene (I) has been proposed to be pheophorbide a monooxygenase, which catalyzes the third step in chlorophyll degradation. Our data (Moffet and Weeden) requires rejection of this hypothesis because the structural gene for Pao maps to a different location on the pea genome than I. In a collaborative effort with researchers in the United Kingdom, we now have strong data suggesting that a different gene is responsible for the cotyledon color polymorphism. In
collaboration with a group at CIAT, we helped identify a practical marker for resistance to bean pod weevil (Blair et al.). We are also continuing to work with intron-targeted markers, and have examined the location of markers from three regions on the pea map on the linkage map for common bean. Synteny appeared to be conserved in only one of the regions examined (a region on pea linkage group V), the markers in the two other regions (pea linkage group III and a portion of pea linkage group VII) being widely distributed on the common bean linkage map.
Impacts
Our use of intron-targeted markers in pea, lentil and common bean has revealed extensive conservation of macrosynteny between pea and lentil, but relatively little conservation of macrosynteny between pea and bean. This finding indicates that genomic comparisons between cool season (Medicago, Pisum, Lens) and warm season (Phaseolus, Glycine, Vigna) legumes will be of limited value until genomic sequences are available for at least one taxon in each group. However, in regions where macrosynteny has been conserved, such as the region of pea linkage group V that matches a region on bean chromosome 1, the positions of genes can be predicted with a high level of confidence and the orthology between genes controlling similar morphological or physiological traits can be identified. Intron-targeted markers also have been shown to amplify orthologous genes in many other legume species and even species outside the family. We expect to eventually have a set of genes that can be
use for mapping in most legume species, permitting map comparison throughout this important family.
Publications
- Gepts, P., W.D. Beavis, E. C. Brummer, R.C. Shoemaker, H.T. Stalker, N.F. Weeden and N.D. Young. 2005. Legumes as a model plant family: genomics for food and feed. Report of the Cross-legume Advances through Genomics (ACTG) conference. Plant Physiol. 137:1228-1235.
- Moffet, M.D. and N.F. Weeden. 2005. Pheophorbide a monooxygenase (Pao) is located on LG VII near Amy in pea and lentil. Pisum Genetics 37:24-29.
- Bai, F. J. Watson, J. Walling, N. Weeden, A.A. Santner and D.A. DeMason. 2005. Molecular characteristic and expression of PsPK2, and PINOID-like gene from pea (Pisum sativum). Plant Sci. 168:1281-1291.
- Blair, M.W., C. Cardona, R. Garza, N. Weeden and S.P. Singh. 2005. Development of a SCAR marker for common bean resistance to the bean pod weevil (Apion godmani Wagner). Bean Improvement Cooperative 48:
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Progress 01/01/04 to 12/31/04
Outputs
We continue to develop sequence-tagged site (STS) markers in legumes. We have expanded our routine screen to include Phaseolus as well as Pisum and Lens. The RIL mapping populations we have available include several that span the genetic diversity in Pisum sativum germplasm, the wide interspecific cross Lens culinaris x L. ervoides, and the BAT x Jalo standard mapping population in Phaseolus vulgaris. Nearly all the markers we have developed display CAPS polymorphism in at least two of the pea RIL populations and usually are polymorphic in the Lens RIL. We are just beginning to assess the level of polymorphism in the bean population, but it appears comparable to that in Lens. We published our findings on the genetic basis of Fusarium root rot tolerance found in the Pisum elatius accession JI1794. The position of several loci in pea of interest to the community working in understanding nitrogen metabolism in legumes were determined with greater accuracy, and the
identify of another gene was clarified by mapping and complementation studies.
Impacts
Comparative mapping in pea, lentil and common bean will facilitate the application of genomic tools developed in these crops and reference legume species to the many other legume crops. The new source of Fusarium root rot tolerance is being introgressed into commercial germplasm and should supplement the current sources of tolerance. Precise mapping of genes involved in nitrogen metabolism will facilitate identification of mutants and quantitative trait loci that affect this process.
Publications
- Hance, S.T., W. Grey and N.F. Weeden 2004. Identification of tolerance to Fusarium solani in Pisum sativum ssp. elatius. Pisum Genetics 36:9-13.
- Grusak, M.A., C.-M. Li, M. Moffet and N.F. Weeden. 2004. Map position of the FRO1 locus in Pisum sativum. Pisum Genetics. 36:6-8.
- Weeden, N.F. 2004. A more precise location for the bronze mutation on LG IV. Pisum Genetics 36:24.
- Weeden, N.F. and M.J. Ambrose. 2004. Ser appears to be the serrate leaflet locus mapped on linkage group III. Pisum Genetics 36:25-26.
- Weeden, N.F., M. Moffet and K.E. McPhee. 2004. The domestication of pea: An analysis of polygenic characters in the Abyssinicum pea supports a semi-independent domestication of this taxon. 5th European Conference on grain legumes (with the ICLGG), Dijon, France.
- Weeden, N.F. and F.J. Muehlbauer. 2004. Genomics and genetic improvement in the cool season pulse crops pea, lentil and chickpea. In: Legume Crop Genomics, R.F. Wilson, H.T. Stalker and E.C. Brummer (eds.) AOCS Press, Champaign, IL pp. 83-96.
- Weeden, N.F., J.A. Walling and M. Moffet. 2004. A comparison of the genetic maps of Pisum, Lens and Medicago indicate disruption of most linkage groups by translocations and other rearrangements. 5th European Conference on grain legumes (with the ICLGG), Dijon, France.
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Progress 01/01/03 to 12/31/03
Outputs
We have continued to develop new sequence-tagged site (STS) markers in pea and lentil. We now have approximately 50 that can be used for comparing among the temperate legumes (tribes Vicieae, Trifolieae, and Cicereae). We have used these markers to identify regions on the pea genome that control root mass, root:shoot ratio and tolerance to Fusarium root rot. Our investigation of a second recombinant inbred population for root mass and root:shoot ratio confirmed most of the regions on the genome that were identified as influencing these characters in the original RI population. We further identified at least two regions that correlated with Fusarium tolerance found in the Pisum elatius accession JI1794. Our work on the flowering genes in Pisum sativum ssp abyssinicum has demonstrated that the genotype of this taxon is Sn, hr, Dne with a unique, early-flowering allele at the Lf locus.
Impacts
The results provide new information to breeders on genes influencing flowering time and root production. The new source of Fusarium root rot tolerance has not been used by breeders and may supplement the current sources of tolerance. The STS primers will promote comparative genomics among legume crops.
Publications
- No publications reported this period
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Progress 01/01/02 to 12/31/02
Outputs
Several traits in pea (Pisum sativum L.) were investigated using molecular markers and a pseudo-QTL analysis. Positions on the linkage map containing genes influencing root mass and root:shoot ratio were identified in a P. s. ssp elatius x P. s. ssp sativum RIL population influencing root mass cosegregated with the locus controlling overall stem height. Two other QTLs with significant effects on root:shoot ratio appeared to cosegregate with genes known to influence flowering time. No correlation was observed between the positions of genes influencing root mass and the position of genes known to influence tolerance to root rot or fusarium wilt. A novel approach to mapping genes with incomplete penetrance demonstrated that an allele of D with incomplete penetrance was responsible for production of anthocyanin on the stems of pea plants as well as its known role in controlling the pattern of anthocyanin in leaf axils. The genetic basis of pod dehiscence in pea was
further clarified, and it was shown that, in addition to Dpo, gp (yellow pod) and a third previously unknown locus had significant effects on this character. A set of primers capable of amplifying homologous sequences in many legumes were described and mapped in pea.
Impacts
The results provide new information to breeders on genes influencing pod dehiscence and root production. The STS primers will promote comparative genomics among legume crops.
Publications
- Brauner, S., R.L. Murphy, J.G. Walling, J. Przyborowski and N.F. Weeden. 2002. STS markers for comparative mapping in legumes. . J. Amer. Soc. Hort. Sci. 127:616-622.
- Weeden, N.F., S. Brauner and J.A. Przyborowski. 2002. Genetic analysis of pod dehiscence in pea (Pisum sativum L.). Cellular & Molecular Biol. Lett. 7:657-663.
- Weeden, N.F. 2002. A suggestion that D is also responsible for stem anthocyanin. Pisum Genetics 34:36-37.
- Weeden, N.F. and M. Moffet. 2002. Identification of genes affecting root mass and root/shoot ratio in a JI1794 x Slow RIL population. .Pisum Genetics 34:28-31.
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Progress 01/01/01 to 12/31/01
Outputs
Progress was made on the genetics of several legume genera. We continued our work on genetic diversity in cowpea (Vigna unguiculata) and other Vigna species. We also compared the taxa in Lupinus section Albus using RAPD markers and determined that these taxa were very closely related and probably do not merit identification as separate species. An analysis of the morphology and genetic markers in the taxon Pisum sativum ssp. abyssinicum demonstrated that the germplasm currently available for this subspecies has a very narrow genetic base, although the taxon is easily distinguished from other subspecies. P. s. abyssinicum apear to represent either a domestication event distinct from that giving rise to P. s. sativum or a scion isolated from the initially cultivated Pisum sativum germplasm. The genetic basis of phenotypic differences between the cultivated pea and wild germplasm was investigated. In addition to the known single gene modifications that exist between
domesticated and wild material, several QTLs influencing flowering time, seed dormancy, pod deshicence and plant height were identified.
Impacts
The analysis of the differences between domesticated pea and wild pea provide a better understanding of which traits will be difficult for breeders to introgress into cultivated pea due to tight linkage with undesirable genes. Understanding the partitioning of genetic diversity in Vigna and Lupinus taxa provides information on which taxa are particularly important as sources of new diversity.
Publications
- Dalbo, M.A., Ye, G.N., Weeden, N.F., Wilcox, W.F., and Reisch, B.I. 2001. Marker-assisted selection for powdery mildew resistance in grapes. J. Amer. Soc. Hort. Sci. 126:83-89.
- Przyborowski, J.A. and Weeden, N.F. 2001. RAPD-based assessment of genetic similarity and distance between Lupinus species in section Albus. J. Appl. Genet. 42:425-433.
- Weeden, N.F. and Wolko, B. 2001. Allozyme analysis of Pisum sativum ssp. abyssinicum and the development of a genotypic definition for this subspecies. Pisum Genetics 33:21-24.
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