Xinjiang wheat stripe rust reveals diverse lineages and uneven resistance breakdown

Wheat stripe rust pathogen populations in Xinjiang displayed substantial genetic and virulence diversity during the 2023 crop season, according to an analysis of 115 isolates of Puccinia striiformis f. sp. tritici. The researchers identified 36 multilocus genotypes, with MLG-10 and MLG-12 predominant in the sample and associated with the broadest virulence profiles. Virulence frequencies exceeded 80% for 11 tested wheat resistance genes, while six other genes had frequencies below 10%, revealing sharply uneven performance across the resistance panel.

The population study focused on isolates collected from major wheat-growing regions of Xinjiang, a major wheat-producing border region connecting China with Central Asia and serving as an epidemiological corridor for pathogen dispersal. Researchers characterized the isolates using 17 simple sequence repeat, or SSR, markers and tested their virulence on 25 Yr isogenic lines and 19 Chinese differential cultivars. They then integrated the genetic and phenotypic data to assess population structure, multilocus genotype diversity and pathotype variation. The study was restricted to the sampled isolates and resistance tests conducted for the 2023 crop season.

Against the 25 isogenic lines, the sampled population showed high virulence frequencies, above 80%, for Yr1, Yr2, Yr6, Yr9, Yr17, Yr18, Yr27, Yr28, Yr29, Yr44 and YrA. These measurements indicate that the corresponding resistance genes were frequently overcome by the tested isolates. In contrast, virulence frequencies remained below 10% for Yr5, Yr8, Yr10, Yr15, Yr32 and YrTr1, which remained highly effective against nearly the entire sampled population. The results therefore show a marked contrast between resistance genes that were frequently overcome and those that retained strong effectiveness in the tested material.

The 36 multilocus genotypes detected among the 115 isolates demonstrated substantial genetic variation within the Xinjiang population. MLG-10 and MLG-12 were the predominant genotypes, and both exhibited broad virulence across multiple Yr genes. The reported association concerns virulence profiles: the study did not establish that either multilocus genotype independently causes greater disease severity, higher crop losses or a specific change in disease incidence. Instead, it linked the two dominant genetic backgrounds to more complex patterns of interaction with the resistance genes tested.

The prevalent race CYR34 was detected across multiple multilocus genotypes, with higher frequencies in MLG-10 and MLG-12 than in the other sampled backgrounds. This showed that the same race phenotype was distributed across several genetic lineages rather than being confined to a single multilocus genotype, while its higher frequency in the two predominant backgrounds revealed an uneven association between genetic structure and that phenotype. By combining SSR-based genetic characterization with virulence testing, the authors described the work as the first comprehensive SSR-based assessment of Pst populations in Xinjiang. They presented the results as a baseline for future surveillance of pathogen population dynamics and said the associations between dominant multilocus genotypes and virulence profiles may support subsequent research on resistance breeding and regional disease surveillance; the study did not test a resistance-breeding intervention or directly evaluate a surveillance program.

Subject of Research: Genetic diversity and virulence variation in Xinjiang wheat stripe rust pathogen populations

Article Title: Genetic structure and virulence profiling of Puccinia striiformis reveal complex pathotype diversity associated with predominant MLG-10 and MLG-12 lineages in Xinjiang

Article References: Awais, M., Ali, S., Batyrbek, M., Li, L., Zhao, J., Kang, Z., & Ma, J. (2026). Genetic structure and virulence profiling of Puccinia striiformis reveal complex pathotype diversity associated with predominant MLG-10 and MLG-12 lineages in Xinjiang. BMC Plant Biology. https://doi.org/10.1186/s12870-026-10071-1

Image Credits: AI Generated

DOI: 10.1186/s12870-026-10071-1

Keywords: wheat stripe rust, Puccinia striiformis, Xinjiang, pathogen genomics, SSR markers, virulence profiles, multilocus genotypes, CYR34, wheat resistance genes, plant disease, Genetic, structure