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Research Project: Improving Control of Stripe Rusts of Wheat and Barley through Characterization of Pathogen Populations and Enhancement of Host Resistance

Location: Wheat Health, Genetics, and Quality Research

Title: Whole-genome sequencing of a sexual population of the wheat stripe rust pathogen identified candidates for avirulence genes

item XIA, CHONGJING - Washington State University
item LEI, YU - Washington State University
item WANG, MEINAN - Washington State University
item Chen, Xianming

Submitted to: Fungal Genetics Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 1/15/2019
Publication Date: 3/20/2020
Citation: Xia, C., Lei, Y., Wang, M., Chen, X. 2020. Whole-genome sequencing of a sexual population of the wheat stripe rust pathogen identified candidates for avirulence genes. Fungal Genetics Conference Proceedings.

Interpretive Summary:

Technical Abstract: Puccinia striiformis f. sp. tritici (Pst) causes stripe rust (yellow rust, Yr), one of the most important diseases of wheat worldwide. To identify avirulence genes in Pst, we developed a segregating population by self-fertilization of U.S. isolate 12-368 (race PSTv-4) on Berberis vulgaris leaves under controlled greenhouse conditions. Virulence testing of the progeny isolates showed segregation of avirulence/virulence phenotypes to nine Yr genes (Yr7, Yr8, Yr17, Yr27, Yr35, Yr41, Yr43, Yr44 and YrExp2). The 117 progeny isolates were whole-genome sequenced at >30x coverage using the Illumina HiSeq PE 150 technology. A total of 2,637 genome-wide high-quality molecular markers were used to construct a genetic map comprising of 47 linkage groups, which spanned 7,715 cM and corresponded to 32 Mb of a reference genome. The recombination rate was estimated at 3.48±3.19 cM/10 kb. Six avirulence genes (AvYr7, AvYr8, AvYr27, AvYr43, AvYr44 and AvYrExp2) were mapped to three locations in the genetic map. Aligning the genetic map to the reference genome narrowed the avirulence locations to small genomic regions. The genomic region of 292 kb harboring avirulence genes AvYr7, AvYr43, AvYr44 and AvYrExp2 contained 73 genes including 24 secreted protein genes, whereas the regions of 135 and 247 kb harboring AvYr8 and AvYr27 contained 33 and 54 genes including 9 and 13 secreted protein genes, respectively. These secreted protein genes can be used as candidates for further studies to determine their functions and clone avirulence genes.