A collaborative study has successfully cloned a crucial avirulence gene, AvrPm6, from the wheat powdery mildew fungus, revealing the direct molecular interaction that activates wheat's resistance. This discovery provides a new target for breeding disease-resistant wheat varieties.
Wheat powdery mildew, a major global disease caused by the fungus Blumeria graminis f. sp. tritici(Bgt), poses a significant threat to wheat production. Understanding the intricate "arms race" between wheat and the pathogen is fundamental to developing sustainable control strategies. While approximately 10 fungal avirulence (Avr) genes and 30 wheat resistance (Pm) genes have been cloned worldwide, the specific molecular mechanisms of their interactions are often poorly understood. Furthermore, the cloning of an AvrPm gene had not been conducted independently by Chinese researchers.
To systematically investigate these interactions, the research group led by Dr. HE Fei at the Institute of Genetics and Developmental Biology (IGDB) of the Chinese Academy of Sciences established a large-scale phenotyping platform. They collected and purified hundreds of genetically diverse Bgt strains and thousands of representative wheat varieties. The team generated hundreds of thousands of interaction phenotypes between the two populations. A specially developed cross-species association mapping algorithm then identified hundreds of potential Pm loci, dozens of AvrPm loci, and their interactions, laying a critical foundation for gene cloning.
In the latest research, Dr. HE's team at IGDB, in collaboration with the group of Professor WANG Xiue from Nanjing Agricultural University, cloned the AvrPm6 gene from this pool of candidates. Through high-throughput phenotyping, GWAS, and expression analysis, the researchers pinpointed the candidate gene for AvrPm6 and validated its function with molecular experiments. They discovered that a single amino acid change in the AvrPm6 protein alters its virulence and, most significantly, that the AvrPm6 protein directly binds to the wheat Pm6 resistance protein to activate the plant's immune response.
The findings, published online on October 21, 2025, in the journal Molecular Plant in a paper titled "Pm6 from Triticum timopheevii encodes an NLR receptor that directly recognizes AvrPm6 to confer powdery mildew resistance in wheat," deepen our understanding of plant-pathogen interactions and provide a clear target for molecular breeding.
The research was supported by the National Key Research and Development Program of China, the National Natural Science Foundation of China, and the Fundamental Research Funds for the Central Universities.
Contact:
Dr. HE Fei
Institute of Genetics and Developmental Biology, Chinese Academy of Sciences
Email: fhe@genetics.ac.cn
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