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ARS Home » Pacific West Area » Pullman, Washington » WHGQ » Research » Publications at this Location » Publication #340553

Research Project: Improved Control of Stripe Rust in Cereal Crops

Location: Wheat Health, Genetics, and Quality Research

Title: Inheritance of virulence, construction of a linkage map, and mapping virulence genes in puccinia striiformis f. sp. tritici by virulence and molecular characterization of a sexual population through genotyping-by-sequencing

Author
item Yuan, Congying - Washington State University
item Wang, Meinan - Washington State University
item Skinner, Daniel - Dan
item See, Deven
item Xia, Chongjing - Washington State University
item Guo, Xinhong - Hunan University Of Science And Technology
item Chen, Xianming

Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/2017
Publication Date: 1/20/2018
Citation: Yuan, C., Wang, M., Skinner, D.Z., See, D.R., Xia, C., Guo, X., Chen, X. 2018. Inheritance of virulence, construction of a linkage map, and mapping virulence genes in puccinia striiformis f. sp. tritici by virulence and molecular characterization of a sexual population through genotyping-by-sequencing. Phytopathology. 108(1):133-141.

Interpretive Summary: Stripe rust is an important disease of wheat, but genetic study of the pathogen virulence was not possible until the recent discovery of alternate hosts. To determine inheritance of virulence and map virulence genes, a segregating population of 119 isolates was developed by self-fertilizing isolate 08-220 on barberry leaves under controlled greenhouse conditions. The progeny isolates were charcaterized by virulence tests and molecular markers, especially genotyping- by-sequencing (GBS) markers. A total of 10,163 polymorphic GBS-SNP markers were identified, and they were grouped into six genetic groups representing six chromosomes. A genetic map consisting of six linkage groups was constructed with 805 markers. Through virulence testing of the progeny isolates, the parental isolate was found to be homozygous for the avirulence loci corresponding to nine resistance genes and homozygous for the virulence locus to one resistance gene. Segregation was observed for virulence phenotypes to the remaining 19 single resistance gene lines. A single dominant gene or two dominant genes with different non-allelic gene interactions were identified for each of the segregating virulence phenotypes. Of 27 virulence genes identified, 17 were mapped to two chromosomes. Markers tightly linked to some of the virulence loci may facilitate further studies to clone these genes. The virulence genes and their inheritance information are useful for understanding the host-pathogen interactions and for for developing stripe rust resistant wheat cultivars.

Technical Abstract: Puccinia striiformis f. sp. tritici (Pst), the wheat stripe rust pathogen, is a dikaryotic, biotrophic, and macrocyclic fungus. Genetic study of Pst virulence was not possible until the recent discovery of Berberis spp. and Mahonia spp. as alternate hosts. To determine inheritance of virulence and map virulence genes, a segregating population of 119 isolates was developed by self-fertilizing Pst isolate 08-220 (race PSTv-11) on barberry leaves under controlled greenhouse conditions. The progeny isolates were phenotyped on a set of 29 wheat lines with single genes for race-specific resistance and genotyped with simple sequence repeat (SSR) markers, simple sequence repeat derived from secreted protein genes (SP-SNP), and SNP markers from genotyping- by-sequencing (GBS). Using the GBS technique, 10,163 polymorphic GBS-SNP markers were identified. Clustering and principal component analysis grouped these markers into six genetic groups, and a genetic map, consisting of six linkage groups, was constructed with 805 markers. The six clusters or linkage groups resulting from these analyses indicated a haploid chromosome number of six in Pst. Through virulence testing of the progeny isolates, the parental isolate was found to be homozygous for the avirulence loci corresponding to resistance genes Yr5, Yr10, Yr15, Yr24, Yr32, YrSP, YrTr1, Yr45, and Yr53 and homozygous for the virulence locus to resistance gene Yr41. Segregation was observed for virulence phenotypes to the remaining 19 single-gene lines. A single dominant gene or two dominant genes with different non-allelic gene interactions were identified for each of the segregating virulence phenotypes. Of 27 virulence genes identified, 17 were mapped to two chromosomes. Markers tightly linked to some of the virulence loci may facilitate further studies to clone these genes. The virulence genes and their inheritance information are useful for understanding the host-pathogen interactions and for selecting effective resistance genes or gene combinations for developing stripe rust resistant wheat cultivars.