Recently, the College of Plant Protection at Northwest A&F University published two research articles titled  "Migration of wheat stripe rust from the primary oversummering region to neighboring regions in China"  in  Communications Biology  and  "Re-delimiting oversummering regions of Puccinia striiformis f. sp. tritici in China"  in  Phytopathology Research. By employing methods such as pathogen virulence analysis, population genetics, airflow trajectory simulations, laboratory experiments, and field monitoring, the researchers redefined the oversummering regions of Pst in China. They identified three core oversummering regions: the high-altitude mountainous areas in southern Gansu, the southern Ningxia (Liupan Mountain), and the spring and late-maturing winter wheat growing areas above 2,000 meters in eastern Qinghai. The study systematically elucidated the spread of wheat stripe rust from oversummering regions to neighboring areas, providing valuable theoretical support for precise monitoring and scientific management of the disease.

Wheat stripe rust is classified as a major crop disease in China, causing severe yield losses annually and posing a significant threat to wheat production and food security. In recent years, global climate change and shifts in agricultural practices have influenced the temperature adaptability and oversummering range of  Pst .

Through systematic simulation experiments, the study found that the dominant Pst races in China, CYR32, CYR33, and CYR34, can grow at an average temperature of 27°C, significantly higher than the previously recognized threshold of 23°C. Based on these findings, the newly identified oversummering regions of Pst include: the role of the northwestern Sichuan oversummering region in the epidemic cycle has diminished. The suitable oversummering area in eastern Gansu has expanded, covering Pingliang and Qingyang in Gansu, as well as Guyuan in southern Ningxia, making it a key oversummering region for  Pst . Extensive oversummering areas were identified in eastern Inner Mongolia and northern Heilongjiang (Figure 1).

Furthermore, the study confirmed three core oversummering regions: the high-altitude mountainous areas in southern Gansu, the southern Ningxia (Liupan Mountain), and the spring and late-maturing winter wheat growing areas above 2,000 meters in eastern Qinghai.

Figure 1. Updated oversummering regions of Puccinia striiformis f. sp. tritici  in China

To further clarify the spread of Pst from the core oversummering regions, the researchers developed a set of KASP-SNP molecular markers and genotyped 308 Pst isolates from oversummering and neighboring regions. Combined with virulence analysis, population genetics, airflow trajectory simulations, and field monitoring (Figure 2), they identified two primary spread routes originating from the northwestern oversummering regions: starting from eastern Qinghai, Pst spreads to the western and eastern regions of Liupan Mountain (eastern Gansu) before reaching the Guanzhong Plain. Originating from central Gansu, the pathogen spreads to Longnan and eastern Gansu, eventually arriving at the Guanzhong Plain (Figure 3). The Guanzhong Plain serves as a key bridge in both routes, facilitating further spread to the major wheat-producing areas in the Huang-Huai-Hai region.

Figure 2. Population genetic structure of Puccinia striiformis f. sp. tritici in the northwestern oversummering regions and neighboring areas

Figure 3. Dispersal pathways of Puccinia striiformis f. sp. tritici from the northwestern oversummering region

Professor Xiaoping Hu from Northwest A&F University and Researcher Qiang Yao from Qinghai University are the corresponding authors of these papers. The first authors are Dr. Yuxiang Li, PhD student Siyue Zhang, and PhD student Jiguang Zhang from Northwest A&F University. Doctoral students Taixue Zhang, Zhibo Zhang, and Junjie Zhang, as well as master's students Di Liu and Jingchen Zhao, participated in the study. Additionally, the research involved contributions from Shiqin Cao and Bo Zhang from the Gansu Academy of Agricultural Sciences, and Xiangming Xu from NIAB.

This study was supported by the National Key R&D Program of China (2021YFD1401000), the National Natural Science Foundation of China (31772102), the 2022 Shaanxi Agricultural Collaborative Innovation Promotion Association Major Science and Technology Project (LMZD202203), the Expansion Project of Northwest A&F University (TGZX2021-13), the International Cooperation Project of the Ministry of Science and Technology (G2023172013L), the China Wheat Research System (CARS-03-37), and the Crop Pest Prediction and Management Innovation Group Project (XYTD2023-04).