Virulence and diversity of Blumeria graminis f. sp. tritici populations in Henan Province, China

(2025) 7:77 Wang et al. Phytopathology Research https://doi.org/10.1186/s42483-025-00366-w Phytopathology Research Open Access RESEARCH Virulence and diversity of Blumeria graminis f. sp. tritici populations in Henan Province, China Junmei Wang1†, Yahong Li1†, Fei Xu1* , Guoyan Zhang2, Chaohong Feng1, Gongqiang Yang1, Yi Liu2, Zihang Han1, Lulu Liu1, Lijuan Li1, Jiaojiao Zhang1, Ruijie Shi1, Xinru Wan1 and Yuli Song1 Abstract Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is an important disease affecting wheat production in Henan Province, China. In this study, 915 isolates from 2011 to 2020 were obtained from 14 cities/counties, virulence assessment was conducted, and SSR markers were employed to analyze the population in 2020. Virulence frequencies, pathotypes, and virulence complexity of the Bgt population from 2011 to 2020, and the population structure of Bgt in 2020 were analyzed. The results demonstrated that (1) no virulent isolates were detected against gene Pm21; (2) the virulence frequencies for genes Pm16, Pm24, PmHYM, Pm2 + Ta, Pm2 + Mld, Pm2 + 6, and Mlxbd remained below 30%; and (3) the virulence frequency for gene Pm2 showed a progressive decline over the study period. The virulence of allisolates, composed of 710 pathotypes, and the analysis of virulence complexity revealed a relatively low diversity. Moreover, the principal component analysis (PCA) of the virulence structure accounted for only 27.78% of the total virulence variation, indicating the virulence profile remained relatively homogeneous from 2011 to 2020 in Henan. The virulence and SSR marker data derived from the Bgt population in 2020 were analyzed using Popgen32 software, revealing no significant correlation between virulence and genetic diversity. The genetic diversity primarily resulted from within-population differences, which accounted for 92.02% of the total variation. The populations were grouped into four clusters, mainly based on geographical proximity, and exhibited extensive gene exchange among populations in 2020. These results provide valuable insights for the rational utilization of Pm genes and enhance our understanding of the diversity in Bgt populations in Henan. Keywords Blumeria graminis f. sp. tritici, Virulence frequency, Pm gene, Virulence complexity, Genetic diversity Background Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is an important disease affecting wheat worldwide. With the widespread adoption of dwarf and † Junmei Wang and Yahong Li have contributed equally to this work. *Correspondence: Fei Xu 1 Institute of Plant Protection, Henan Academy of Agricultural Science/Key Laboratory of Integrated Pest Management On Crops in Southern Part of North China, Ministry of Agriculture and Rural Affairs of the People’s Republic of China, Zhengzhou 450002, China 2 Henan Plant Protection and Quarantine Station, Zhengzhou 450000, China semi-dwarf wheat varieties and improved fertilizer and water conditions, wheat powdery mildew has been one of the most prevalent diseases in wheat cultivation. Growing resistant varieties is the most cost-effective and efficient disease management strategy. However, the pathogen often evolves to overcome the commonly used resistance genes, leading to an increase in the prevalence of virulent strains (McDonald and Linde 2002). The dissemination of resistant varieties carrying one or several Pm genes has resulted in the loss of resistance governed by certain genes, such as Pm8 (Huang et al. 2015; Li et al. 2019). Wheat powdery mildew represents a host-parasite system with a gene-for-gene relationship. Near-isogenic © The Author(s) 2025. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. Wang et al. Phytopathology Research (2025) 7:77 lines or single-gene varieties carrying known resistance genes were commonly employed as differential hosts to ascertain pathogen virulence (Wolfe and Schwarzbach 1975, 1978; Li and Huang 1992). Virulence data derived from these populations facilitate the prioritization of Pm genes for incorporation into breeding programs (Heun 1987). Ma et al. (2008) compared physiological races and virulence analysis of Bgt, concluding the direct virulence frequency analysis against known resistance genes, and simplified data processing and analysis. The approach is valuable for monitoring shifts of virulent genes and the validity of resistance genes in hosts. The virulence frequency in Bgt populations varies within and across different regions in China due to the extensive wheat-growing area, the multitude of wheat varieties, and diverse ecological conditions (Duan et al. 1998). Therefore, regional studies on the virulence and genetic structure of Bgt populations are essential for designing local disease management strategies. Henan Province, situated in the transitional zone between the subtropical and warm temperate climates, exhibits an environment conducive to the cultivation of a diverse range of plants (Zhang 2000). As a key region of wheat production, a staple crop in China, the wheat planting area in Henan has remained consistently above 56,130 square kilometers in recent years, contributing approximately a quarter of total grain output in China (Ye 2023). However, wheat powdery mildew is a prevalent disease, affecting at least 600,000 hectares annually and emerging as a significant constraint on wheat production safety in the area (Peng 2023). The majority of wheat varieties currently cultivated in Henan are susceptible to wheat powdery mildew, and chemical controls are the primary strategy for disease management (He et al. 2001; Cao et al. 2021). Unfortunately, the application of pesticides in practice has surpassed the levels necessary for effective disease prevention and control, leading to potential environmental and food safety hazards (Liu et al. 2002; Ma 2013). Therefore, it is crucial to enhance the monitoring of Bgt virulence and to advance research on its pathogenicity for informing the strategic distribution of wheat varieties with effective resistance. Numerous studies have been conducted to monitor the shifts of virulence of Bgt population in Henan (Wang e (...truncated)