Surveillance of dispersal and virulence variation of southern corn rust pathogen

The project aims to investigate the dispersal and pathogenicity variation of two transnational crop diseases, Common Corn Rust and Southern Corn Rust (SCR) in China, Thailand, Philippines, and Uzbekistan. About 250 CCR/SCR samples will be collected from these four countries from 2023 to 2024. The RNA of infected corn leaves and rust spores will be extracted together and sequenced in a 350bp pair-read library. By mapping to the high-quality reference genome of two pathogens (Puccinia polysora, Ppz and P. sorghi, Psz) (phased haplotype genomes supplied by Party A), we would like to evaluate the genetic diversity, population structure, and phylogeny of these two pathogens among four countries, and draw a full map of dispersal routes of these two diseases in Asia. In addition, the high-throughput data will supply accurate variation loci of virulence-related genes, e.g., effectors. The outputs of this project will be useful to answer the origin, lifecycle, and dispersal routes of Ppz and Psz. More importantly, these data will build a database including all pathogenicity genotypes, which will be greatly beneficial for resistance breeding. We aim to set the database as a model to reach out to Europe, North America, Africa, and other regions and finally organize a global research alliance to perform joint prevention for transnational crop diseases.