title: Virulence Structure of Blumeria graminis f. sp. tritici and Its Genetic Diversity by ISSR and SRAP Profiling Analyses.
abstract: Blumeria graminis f. sp. tritici, which causes wheat powdery mildew, is an obligate biotrophic pathogen that can easily genetically adapt to its host plant. Understanding the virulence structure of and genetic variations in this pathogen is essential for disease control and for breeding resistance to wheat powdery mildew. This study investigated 17 pathogenic populations in Sichuan, China and classified 109 isolates into two distinct groups based on pathogenicity analysis: high virulence (HV, 92 isolates) and low virulence (LV, 17 isolates). Populations from Yibin (Southern region), Xichang (Western region), and Meishan (Middle region) showed lower virulence frequencies than populations from other regions. Many of the previously known resistance genes did not confer resistance in this study. The resistance gene Pm21 displayed an immune response to pathogenic challenge with all populations in Sichuan, and Pm13, Pm5b, Pm2+6, and PmXBD maintained resistance. AMOVA revealed significantly higher levels of variation within populations and lower levels of variation among populations within regions. High levels of gene flow were detected among populations in the four regions. Closely related populations within each region were distinguished by cluster analyses using ISSR and SRAP alleles. Both ISSR and SRAP allele profiling analyses revealed high levels of genetic diversity among pathogenic populations in Sichuan. Although ISSR and SRAP profiling analysis showed similar resolutions, the SRAP alleles appeared to be more informative. We did not detect any significant association between these alleles and the virulence or pathogenicity of the pathogen. Our results suggest that ISSR and SRAP alleles are more efficient for the characterization of small or closely related populations versus distantly related populations.
authors.affiliation: College of Agronomy, Sichuan Agricultural University, Chengdu, Sichuan, China.
authors.forename: Na
authors.initials: N
authors.lastname: Liu
authors.affiliation: National Center for Agricultural Utilization Research, Agricultural Research Service, U.S. Department of Agriculture, Peoria, Illinois, United States of America.
authors.forename: Z Lewis
authors.initials: ZL
authors.lastname: Liu
authors.affiliation: College of Agronomy, Sichuan Agricultural University, Chengdu, Sichuan, China.
authors.forename: Guoshu
authors.initials: G
authors.lastname: Gong
authors.affiliation: College of Agronomy, Sichuan Agricultural University, Chengdu, Sichuan, China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.affiliation: College of Resources, Sichuan Agricultural University, Chengdu, Sichuan, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Wang
authors.affiliation: College of Agronomy, Sichuan Agricultural University, Chengdu, Sichuan, China.
authors.forename: You
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: College of Agronomy, Sichuan Agricultural University, Chengdu, Sichuan, China.
authors.forename: Xiaobo
authors.initials: X
authors.lastname: Qi
authors.affiliation: College of Agronomy, Sichuan Agricultural University, Chengdu, Sichuan, China.
authors.forename: Huabao
authors.initials: H
authors.lastname: Chen
authors.affiliation: College of Agronomy, Sichuan Agricultural University, Chengdu, Sichuan, China.
authors.forename: Jizhi
authors.initials: J
authors.lastname: Yang
authors.affiliation: College of Agronomy, Sichuan Agricultural University, Chengdu, Sichuan, China.
authors.forename: Peigao
authors.initials: P
authors.lastname: Luo
authors.affiliation: College of Agronomy, Sichuan Agricultural University, Chengdu, Sichuan, China.
authors.forename: Chunping
authors.initials: C
authors.lastname: Yang
mesh_terms: D000483:Alleles; D001203:Ascomycota / Q000235:genetics*; D002681:China; D020869:Gene Expression Profiling / Q000379:methods; D051456:Gene Flow / Q000235:genetics; D014644:Genetic Variation / Q000235:genetics*; D010935:Plant Diseases / Q000382:microbiology; D014908:Triticum / Q000382:microbiology; D014774:Virulence / Q000235:genetics*