Inheritance of virulence and linkages of virulence genes in an Ethiopian isolate of the wheat stripe rust pathogen (Puccinia striiformis f. sp. tritici) determined through sexual recombination on Berberis holstii

Authors: SIYOUM, GEBRESLASIE - Northwest Agricultural & Forestry University; ZENG, QINGDONG - Northwest Agricultural & Forestry University; ZHAO, JIE - Northwest Agricultural & Forestry University; Chen, Xianming; BADEBO, AYELE - International Maize & Wheat Improvement Center (CIMMYT); TIAN, YUAN - Northwest Agricultural & Forestry University; HUANG, LILI - Northwest Agricultural & Forestry University; KANG, ZHENSHENG - Northwest Agricultural & Forestry University; ZHAN, GANGMING - Northwest Agricultural & Forestry University

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/17/2019
Publication Date: 4/24/2019
Citation: Siyoum, G.Z., Zeng, Q., Zhao, J., Chen, X., Badebo, A., Tian, Y., Huang, L., Kang, Z., Zhan, G. 2019. Inheritance of virulence and linkages of virulence genes in an Ethiopian isolate of the wheat stripe rust pathogen (Puccinia striiformis f. sp. tritici) determined through sexual recombination on Berberis holstii. Plant Disease. 103(9):2451-2459. https://doi.org/10.1094/PDIS-02-19-0269-RE.
DOI: https://doi.org/10.1094/PDIS-02-19-0269-RE

Interpretive Summary: Stripe rust is one of the most devastating wheat diseases in Ethiopia. To study virulence genetics of the pathogen, 117 progeny isolates were produced through sexual reproduction of an Ethiopian isolate of the stripe rust pathogen on plants of a barberry species under controlled conditions. The parental and progeny isolates were characterized by testing on wheat lines each carrying a single gene for resistance to stripe rust and genotyped using ten polymorphic simple sequence repeated (SSR) markers. The progeny isolates were classified into 37 virulence phenotypes and 75 multi-locus genotypes. The parent isolate and progeny isolates were all avirulent to resistance genes Yr5, Yr10, Yr15, Yr24, Yr32, YrTr1, YrSP, and Yr76, but virulent to Yr1 and Yr2, indicating that the parent isolate was homozygous avirulent or homozygous virulent at these loci. The progeny isolates segregated for virulence to 12 Yr genes. Virulence phenotypes to Yr6, Yr28, Yr43, and Yr44 each was controlled by a single dominant gene; those to Yr7, Yr9, Yr17, Yr27, Yr25, Yr31, and YrExp2 each was controlled by two dominant genes; and the virulence phenotype to Yr8 was controlled by two complementary dominant genes. A linkage map was constructed with seven SSR markers, and 16 virulence loci corresponding to 11 Yr resistance genes were mapped with some loci linked to each other. The results are useful in understanding the host-pathogen interactions and selecting resistance genes to develop wheat cultivars with highly effective resistance to stripe rust.

Technical Abstract: Stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most devastating wheat diseases in Ethiopia. To study virulence genetics of the pathogen, 117 progeny isolates were produced through sexual reproduction of an Ethiopian isolate of the stripe rust pathogen on plants of Berberis holstii under controlled conditions. The parental and progeny isolates were characterized by phenotyping on wheat lines carrying single Yr genes for resistance and genotyped using ten polymorphic simple sequence repeated (SSR) markers. The progeny isolates were classified into 37 virulence phenotypes and 75 multi-locus genotypes. The parent isolate and progeny isolates were all avirulent to resistance genes Yr5, Yr10, Yr15, Yr24, Yr32, YrTr1, YrSP, and Yr76, but virulent to Yr1 and Yr2, indicating that the parent isolate was homozygous avirulent or homozygous virulent at these loci. The progeny isolates segregated for virulence to 12 Yr genes. Virulence phenotypes to Yr6, Yr28, Yr43, and Yr44 each was controlled by a single dominant gene; those to Yr7, Yr9, Yr17, Yr27, Yr25, Yr31, and YrExp2 each was controlled by two dominant genes; and the virulence phenotype to Yr8 was controlled by two complementary dominant genes. A linkage map was constructed with seven SSR markers, and 16 virulence loci corresponding to 11 Yr resistance genes were mapped with some loci linked to each other. The results are useful in understanding the host-pathogen interactions and selecting resistance genes to develop wheat cultivars with highly effective resistance to stripe rust.