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ARS Home » Pacific West Area » Pullman, Washington » WHGQ » Research » Publications at this Location » Publication #324119
Title: Association analysis of SP-SNPs and Avr genes in Puccinia striiformis f. sp. tritici, the wheat stripe rust pathogen

Author
item XIA, CHONGJIN - Washington State University
item WANG, MEINAN - Washington State University
item WAN, ANMIN - Washington State University
item JIWAN, DERICK - Washington State University
item See, Deven
item Chen, Xianming

Submitted to: American Journal of Plant Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/17/2015
Publication Date: 1/27/2016
Citation: Xia, C., Wang, M., Wan, A., Jiwan, D.A., See, D.R., Chen, X. 2016. Association analysis of SP-SNPs and Avr genes in Puccinia striiformis f. sp. tritici, the wheat stripe rust pathogen. American Journal of Plant Sciences. 7:126-137.

Interpretive Summary: Wheat stripe rust is a great threat for wheat production all over the world. Intensive efforts have been made to study genetics of wheat resistance to this disease, but few on avirulence of the pathogen due mainly to the nature of obligate biotrophism and the lack of systems for studying its genetics and molecular manipulations. To overcome these limitations, a natural stripe rust pathogen population comprising 352 isolates representating a diverse virulence spectrum was genotyped using 97 secreted protein – single nucleotide polymorphism (SP-SNP) markers to identify candidate avirulence genes using association analysis. Among avirulence genes corresponding to 19 resistance genes, significantly associated SP-SNP markers were detected for avirulence genes AvYr1, AvYr2, AvYr6, AvYr7, AvYr8, AvYr44, AvYrExp2, AvYrSP, and AvYrTye. These preliminary results indicate that association analysis can be used to identify markers for avirulence genes. However, caution should be paid to interpret these results because of false-positive associations possibly due to population structures. Although no perfectly associated markers were obtained for any of the avirulence genes, this study has laid the foundation for developing more SP-SNPs, analyzing them for association with avirulence genes, and verifying them using mapping populations that can be generated through sexual reproduction on alternate hosts of the pathogen.

Technical Abstract: Puccinia striiformis f. sp. tritici (Pst) is one of the pathogenic fungi on wheat, caused stripe rust disease which is a great threat for wheat production all over the world. Intensive efforts have been made to study genetics of wheat resistance to this disease, but few on avirulence of the pathogen due mainly to the nature of obligate biotrophism and the lack of systems for studying its genetics and molecular manipulations. To overcome these limitations, a natural Pst population comprising 352 isolates representative of a diverse virulence spectrum was genotyped using 97 secreted protein – single nucleotide polymorphism (SP-SNP) markers to identify candidate avirulence genes using association analysis. Among avirulence genes corresponding to 19 resistance genes, significantly associated SP-SNP markers were detected for avirulence genes AvYr1, AvYr2, AvYr6, AvYr7, AvYr8, AvYr44, AvYrExp2, AvYrSP, and AvYrTye. These preliminary results indicate that association analysis can be used to identify markers for avirulence genes. However, caution should be paid to interpret these results because of false-positive associations possibly due to population structures. Although no perfectly associated markers were obtained for any of the avirulence genes, this study has laid the foundation for developing more SP-SNPs, analyzing them for association with avirulence genes, and verifying them using mapping populations that can be generated through sexual reproduction on alternate hosts of the pathogen.