Identification of Quantitative Trait Loci and Analysis of Novel Candidate Genes for Resistance to False Smut of Rice...

Rice false smut (RFS), an emerging disease caused by the fungus Ustilaginoidea virens (Cooke), reduces rice grain yield and quality in rice-planting regions worldwide. The identification of the genes or quantitative trait loci (QTLs) associated with RFS resistance is vital to resistance breeding and the mitigation of RFS damage. In this study, RFS resistance QTLs were located in the resistant variety IR77298-14-1-2::IRGC117374-1. A total of 4 RFS resistance QTLs were detected on rice chromosomes 1, 3, 5, and 12 in the F₂ and F₄ mapping populations using 119 polymorphic simple sequence repeat (SSR) molecular markers. Of these QTLs, qRFS3.01 and qRFS12.01-1 were repeatedly detected in both populations. Interestingly, QTL qRFS3.01 on chromosome 3 is a novel resistance locus that exhibited the largest phenotypic effect. These results suggest that SSR markers linked to qRFS3.01 are valuable for marker-assisted breeding for RFS resistance in rice. The prediction of putative candidate genes within qRFS3.01 revealed three resistance-related proteins containing an F-box domain, Myb-like DNA-binding domain, and kinase protein. In summary, our findings provide new QTLs/genes for resistance to RFS and will promote rice disease resistance through molecular-marker-assisted breeding.