Countrywide inter‐epidemic region migration pattern suggests the role of southwestern population in wheat stripe rust epidemics in China

Abstract

Understanding countrywide pathogen population structure and inter‐epidemic region spread is crucial for deciphering crop potential losses. Wheat stripe rust caused by Puccinia striiformis f. sp. tritici is a destructive disease that affects worldwide wheat production, widespread in China, representing largest epidemic region globally. This study aimed to understand the population structure and migration route of P. striiformis f. sp. tritici across China based on sampling from 15 provinces representing six epidemic zones, viz., over‐summering, over‐wintering, eastern, Yun‐Gui, Xinjiang and Tibet epidemic regions. High genotypic diversity was recorded in over‐summering, Tibet and over‐wintering epidemic regions. Epidemic regions partly explain population subdivision with variable divergence (FST = 0.005–0.344). Xinjiang and Tibet epidemic regions were independent epidemic zones with least sharing of genotypes. Among other epidemic zones, i.e. over‐summering, over‐wintering, eastern and Yun‐Gui epidemic zones, re‐sampling MLGs, clustering‐based structure, DAPC analyses, relative migration and low divergence (FST from 0.006 to 0.073) revealed frequent geneflow. Yun‐Gui epidemic regions, with a potential for both over‐summering and over‐wintering, could play an important role in causing epidemics in main wheat‐cultivating areas of China. High diversity, recombination signatures and inter‐epidemic region migration patterns need to be considered in host‐resistant cultivar development in China and neighbouring countries, considering risk of long‐distance migration capacity of pathogen.

Identification of Puccinia striiformis races from the spring wheat crop in Xinjiang, China

“…Understanding the dynamics of races within different host crops and seasons is vital to break up the regional pathogen life cycle. Xinjiang is one of the most important epidemic regions for wheat stripe rust not only for China but also for Central Asian countries due to its geographic proximity ( Awais et al., 2022 ; Chen et al., 2023 ). Very limited research was conducted on race identification in this region.…”

“…Recently, high genetic diversity and recombination populations were reported in China’s north and south epidemic regions. Moreover, these epidemic regions provide inoculum to cause epidemics in other regions of the country ( Awais et al., 2022 ). China has been a primary focus of stripe rust for researchers after the Himalayan region was found as a center of diversity for the worldwide Pst populations ( Ali et al., 2014 ).…”

“…The vast region of Xinjiang in northwestern China is important for stripe rust epidemics. As it is located in the potential center of diversity ( Ali et al., 2014 ; Awais et al., 2022 ), the region links other Chinese epidemic regions to Central Asia ( Chen et al., 2023 ). Also, both winter and spring wheat crops grown in this region and mild summer temperatures provide a long season of host plants and favorable environmental conditions for Pst to infect, develop, and survive.…”

Fighting wheat rusts in China: a look back and into the future

“…As a result, this epidemiological region is almost isolated from other regions. However, recent studies revealed that the Yunnan epidemiological region and other southwestern epidemiological regions are also involved in wheat stripe rust epidemics in China (Awais et al 2022;Huang et al 2022;Ju et al 2022;Zhan et al 2022a). In addition to Yunnan region, Tibet and Xinjiang also developed to be the independent stripe rust epidemiological regions (Li and Zeng 2002;Hu et al 2017;Awais et al 2022).…”

“…However, recent studies revealed that the Yunnan epidemiological region and other southwestern epidemiological regions are also involved in wheat stripe rust epidemics in China (Awais et al 2022;Huang et al 2022;Ju et al 2022;Zhan et al 2022a). In addition to Yunnan region, Tibet and Xinjiang also developed to be the independent stripe rust epidemiological regions (Li and Zeng 2002;Hu et al 2017;Awais et al 2022). Importantly, Xinjiang and other Chinese provincial Pst populations are all isolated from that of Pakistan due to extremely high genetic divergence (Awais et al 2023).…”