Progress 10/01/15 to 09/30/18
Outputs
Target Audience:A primary target audience is the large community of soybean researchers, specifically in the areas of molecular biology, genetics, and breeding. A major stakeholder group relevant to the project is the New York Corn and Soybean Growers Association, whose members have experienced serious soybean yield losses from this pathogen, particularly in the 2014 growing season. In addition, the project is highly relevant for the members of the Northeast Organic Farming Association-NY, who likely will also be interested in the perennial nature of the Glycine species that are the focus of the study. New York County Agricultural Extension Field Crop Agents will also be interested in identifying resistance to white mold. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?Poster presentation of results was made by Dr. Sue Sherman-Broyles at the Soy2016 meeting in Columbus, OH, in August, 2016. Dr. Sherman-Broyles participated in Outreach in January of 2016 and 2017. As a plant biologist, this project was described to young girls in 4th through 8th grade at a Girl's Day Out event. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Cultivated soybean suffers from having little genetic variation to use to develop cultivars that are resistant to pathogens. The perennial wild relatives of soybean lack agronomic traits that would be useful in increasing yield or seed quality but do however harbor resistance to pathogens that cultivated soybean lacks. We identified many accessions among many species of the perennial wild relatives of soybean that are resistant to a virulent strain of white mold isolated in New York State. This is the first step in identifying the genomic regions responsible for durable resistance to a pathogen that decreases yields. We identified two diploid species that include both resistant and susceptible individuals suitable for further study. Glycine tomentella D3, and G. stenophita which is a sub-tropical to temperate species that has more resistant phenotypes than other diploid species screened. Allopolyploids were previously found to harbor many resistant accessions but diploids make mapping efforts simpler. Glycine stenophita is a diploid contributor to allopolyploids G. tabacina and G. pescadrensis which will be a focus in further studies. For success in future iterations of this project, a resistant G. stenophita accession was sequenced. Raw data from PacBio sequencing, Hi-C scaffolding and short read Illumina sequencing are now available to collaborators who will assemble a draft genome. This reference will vastly improve the ability to identify loci underlying resistance traits, particularly those that are not found in the soybean reference genome. Description of progress on individual major goals: 1. Screen perennialGlycinespecies for resistance to a white mold. 1) We screened over 1000 plants across wild perennial species. To do so we have modified techniques developed for soybean. We have identified species that are unsuitable for further investigation due to growth habit or inability to generate adequate amounts of seed. From these screens we chose two diploid species to focus on. 2) Each plant screened was inoculated with white mold and scored for response to pathogen. Twenty accessions of Glycine tomentella D3 and G. stenophita were screened in a minimum of three replicate experiments. 3) No single species showed complete resistance to the NY strain of white mold but rather accessions varied in their responses. Glycine tomentella D3 had a wider range of responses, two accessions were nearly completely resistant while nearly all of the remaining 18 accessions were severely impacted. Glycine stenophita had 5 accessions that were nearly completely resistant and the remaining 15 accessions were mildly impacted. 4) The number of accessions in the replicated portion of the screenings were ultimately reduced to just twenty because of two main factors. One of the factors were issues with seed germination or multiplication, but the greatest impact to decreasing the number of accessions were results from a companion project investigating genome-wide genetic variation using SNPs. These results indicated that accessions within G. tomentella D3 were actually a cryptic sister species and not as closely related to the core G. tomentella D3 as originally thought. Those accessions were removed from the project. Within what was thought to be G. stenophita are outliers as well as mis-identified allopolyploids. 2. Compare results with Hartman et al. (2000). 1) Hartman et al (2000) found G. tabacina to have the most accessions with partial resistance to white mold. Glycine tabacina, in the broad sense of the species includes both diploid and allopolyploid species. The diploid species are members of the B genome group, the allopolyploid and likely true G. tabacina is an allopolyploid combining B genome species and G. stenophita. We grew many B genome group diploids for screening but screening was not successful in most. The Hartman group has since focused on Glycine latifolia and we did not replicate their work, instead concentrating on G. stenophita. 2) Very little data were collected from B genome diploids. Many of the putative species with temporary designations cracens, wilsonii small and large, have very thin, weak stems with extremely short internodes at the base of the plant. These characteristics were not conducive to screening large numbers of plants. 3) Only 85 plants were screened from each of "G. cracens" and G. latifolia. Fewer than 50 plants were screened for G. microphylla and "G. wilsonii". Screenings indicated that most accessions were resistant. Many unscored plants continued to grow in a fashion that pushed the inoculum off the plant, either the plants grew too fast to screen or were so robustly resistant allowing the plant to grow despite being cut and inoculated. 4) These results caused us to focus specifically on G. tomentella D3 and G. stenophita. 3. Evaluate resistance/susceptibility in perennial soybeans. 1) As part of our screening we included accessions of allopolyploids G. dolichocarpa, G. tabacina, and G. pescadrensis. G. tomentella D3 is a progenitor of G. dolichocarpa as well as another diploid G. syndetika which was also screened. G. stenophita is a diploid progenitor of G. tabacina and G. pescadrensis. G. syndetika also is a genome donor of G. pescadresis. 2) Four accessions of G. dolichocarpa were screened. One each of G. pescadrensis and G. tabacina. 3) Twenty-five percent of G. dolichocarpa screened had limited resistance while the remaining accessions were highly susceptible similar to G. syndetika. G. pescadrensis accession was relatively resistant, similar to G. stenophita. G. tabacina was relatively resistant, similar to G. stenophita. 4) This work will continue in the subsequent project with collaborator Georg Jander. Previous work on aphid resistance in G. dolichocarpa discovered transgressive resistance, the allopolyploid combining the types of resistance found in the diploid progenitors. 4. Make crosses between resistant and susceptible accessions. 1) Susceptible and resistant accessions for G. tomentella D3 and G. stenophita were grown to make crosses. These perennial plants have not flowered yet and work will continue in a subsequent project with Georg Jander's lab. Genome-wide association studies (GWAS) in G. tomentella D3 and G. stenophita were investigated using genome-wide SNP data generated from a complementary Multi-state project. Preliminary GWAS analyses included principal component analysis (PCA). PCA, along with network analyses from the Multi-state project indicated that we were using accessions that were outliers and not similar to the majority of accessions in the analyses. The Multi-state project has allowed us to identify many, previously unknown, sister species and mis-identified accessions. 2) A total of 33 "G. tomentella D3" accessions were grown and scored for resistance to white mold and a total of 38 "G. stenophita" accessions were grown and scored. Network analysis of genome-wide SNPs reduced the number of accessions with proper ID to just 20 in each species. 3) Discovery of accessions that do not belong in GWAS has drastically reduced the G. stenophita and G. tomentella D3 accessions. Just 20 accessions in each species had adequate germination rates and seed numbers to screen resistance response with appropriate replication. The decrease in numbers negates the power GWAS has to identify chromosome regions responsible for resistance. 4) The perennial wild relatives of soybean are not amenable to GWAS because there are not enough accessions within species to have power to distinquish genomic regions responsible for disease resistance. 5. Study relevant genetic regions in resistant and susceptible perennialGlycinespecies: Nothing to report. Findings from a subsequent project will address these goals.
Publications
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Progress 10/01/15 to 09/30/16
Outputs
Target Audience:Dr. Sue Sherman-Broyles presented a poster on this work at the Soy2016 meeting in Columbus, OH, in August, 2016. Changes/Problems:We moved from a greenhouse-based design to a growth chamber design, which delayed the collecting of consistent data. There was a steep learning curve associated with adapting infection protocols from soybean to the much smaller perennial soybean relatives. What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?Poster presentation of results was made by Dr. Sue Sherman-Broyles at the Soy2016 meeting in Columbus, OH, in August, 2016. What do you plan to do during the next reporting period to accomplish the goals?Continue screening accessions to reach goals of approximately 600 accessions, emphasizing G. stenophita and allopolyploid species.
Impacts
What was accomplished under these goals?
1. Screened approximately 300 accessions of perennial Glycine species (over 750 plants, total) for resistance to a New York isolate of white mold (Sclerotinia sclerotiorum) known to be aggressive on soybean. 2. Nothing yet 3. Have evaluated resistance in the allopolyploid G. dolichocarpa and its two diploid progenitors (G. syndetika, G. tomentella D3); these same diploid species are also relevant to several other allopolyploid species, notably G. pescadrensis, which is another targeted allopolyploid species. We have also begun screening the other diploid progenitor of G. pescadrensis (G. stenophita) as well as diploid species relevant to other allopolyploids. 4. We are in the process of evaluatingG. tomentella D3 accessions for making crosses. 5. Nothing yet
Publications
- Type:
Other
Status:
Published
Year Published:
2016
Citation:
Poster 077 at https://caps.osu.edu/soy2016/abstracts-posters/abstracts/poster
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