Location: Cereal Crops Research2018 Annual Report
Objective 1: Identify novel sources of disease and pest resistance in durum wheat and goatgrass to enhance crop resilience. [NP301, C1, PS1B] Objective 2: Map and characterize novel genes governing resistance/susceptibility to tan spot, Septoria nodorum blotch, stem rust, and Hessian fly in wheat and goatgrass to develop the knowledge and tools for their deployment in the development of wheat varieties with improved resistance. [NP301, C1, PS1A] Objective 3: Characterize genetic mechanisms associated with wheat-pathogen interactions to increase our understanding and knowledge of the biological mechanisms associated with resistance and susceptibility. [NP301, C3, PS3A] Objective 4: Utilize and develop genetic resources and molecular tools for the improvement of wheat and provide genotyping services to expedite the development of improved wheat, barley and oat varieties. [NP301, C1, PS1A and PS1B] Objective 5: Genetically improve barley by the application of molecular genetics and genomics to increase resistance to head and foliar diseases such as Fusarium head blight, net blotch and spot blotch. [NP301, C1, PS1A and PS1B]
Durum and hard red spring wheat (HRSW) varieties with improved resistance to diseases and pests are needed to meet the demands of the world’s growing population. This challenge must be met through the discovery, characterization, and deployment of genes for resistance to biotic stresses. In this project, we will identify new sources of resistance to Septoria nodorum blotch, tan spot, and stem rust in durum, and to Hessian fly in goatgrass. Molecular mapping and genetic analyses will be used to identify and characterize genes and quantitative trait loci governing resistance to tan spot, Septoria nodorum blotch, and stem rust. This work will yield knowledge of the genetic mechanisms controlling these traits, the development of markers for marker-assisted selection, and genetic stocks and germplasm useful for gene deployment. Additional work on the molecular characterization of the genes and genetic pathways associated with wheat-pathogen interactions will be conducted as part of this project and will yield basic knowledge useful for devising novel strategies for developing disease and pest resistant varieties. Finally, genetic resources and tools for the development of improved wheat and durum cultivars will be generated, including stocks for the genetic analyses of Septoria nodorum blotch susceptibility genes and Hessian fly resistance genes, adapted germplasm with low cadmium and resistance to sawfly, Fusarium head blight, and stem rust, and a reference sequence-based genetic map for durum wheat. In addition, genotyping services will be provided to regional wheat, durum, barley, and oat breeders to expedite the development of improved varieties.
This is the first report for the new project 3060-21000-038-00D, which began in March 2018, upon completion of project 3060-21000-037-00D. Most progress from FY18 is included in the annual report for 3060-21000-037-00D, and therefore there is little to report for 3060-21000-038-00D. However, seeds of the 960 durum wheat accessions of the durum wheat reference collection have been obtained, grown in quarantine, and harvested. Once threshed and catalogued, we will be able to begin phenotyping the collection for various traits to assess diversity and identify durum lines with novel disease resistance. Toward the identification and cloning of the necrotrophic effector sensitivity gene Snn5 in wheat, the appropriate high-resolution mapping populations have been constructed and partially phenotyped. New molecular markers have been developed that delineate the candidate region to several hundred megabase pairs of DNA. Appropriate crosses have been made between the durum cultivar Kronos and emmer wheat accessions for the development of segregating populations that will allow us to evaluate the genetics of tan spot resistance derived from Kronos. To identify the stem rust resistance gene in Ae. tauschii accession RL5271, a population of 366 F2 plants from the cross between Ae. tauschii RL5271 and AL8/78 have been evaluated for seedling reactions to stem rust race TPMKC at the seedling stage and were genotyped with a set of D-genome specific SSR markers. The stem rust and marker data will allow us to locate the stem rust resistance gene from RL5271 through genetic analysis and gene mapping. Initial crosses and backcrosses between gene donors and recipient parents have been made to develop wheat lines nearly isogenic for Parastagonospora nodorum necrotrophic effector sensitivity genes and Hessian fly resistance genes. Attempts to express effector-like proteins identified from F. graminearum in yeast have been started and two such recombinant proteins (one PR-1-like and one Kp4 killer toxin-like) have been obtained. These two proteins are being purified and their potential biological activities will be evaluated.