Ce Deng, April Leonard, James Cahill, Meng Lv, Yurong Li,Shawn Thatcher, Xueying Li, Xiaodi Zhao, Wenjie Du, Zheng Li, Huimin Li,Victor Llaca, Kevin Fengler, Lisa Marshall, Charlotte Harris, Girma Tabor, Zhimin Li,Zhiqiang Tian, Qinghua Yang, Yanhui Chen, Jihua Tang, Xintao Wang, Junjie Hao,Jianbing Yan, Zhibing Lai, Xiaohong Fei, Weibin Song, Jinsheng Lai, Xuecai Zhang,Guoping Shu, Yibo Wang, Yuxiao Chang, Weiling Zhu, Wei Xiong, Juan Sun,*,Bailin Li,* and Junqiang Ding* 

Southern corn rust (SCR), caused by the fungal pathogen Puccinia polysora, is a major threat to maize production worldwide. Efficient breeding and deployment of resistant hybrids are key to achieving durable control of SCR. Here, we report the molecular cloning and characterization of RppC, which encodes an NLR-type immune receptor and is responsible for a major SCR resistance quantitative trait locus. Furthermore, we identified the corresponding avirulence effector, AvrRppC, which is secreted by P. polysora and triggers RppC-mediated resistance. Allelic variation of AvrRppC directly determines the effectiveness of RppC-mediated resistance, indicating that monitoring of AvrRppC variants in the field can guide the rational deployment of RppC-containing hybrids in maize production. Currently, RppC is the most frequently deployed SCR resistance gene in China, and a better understanding of its mode of action is critical for extending its durability.