Identification of qPSR7-2 as a Novel Cold Tolerance-Related QTL in Rice Seedlings on the Basis of a GWAS

Abstract

Rice is the primary source of food for more than half of the global population. Accordingly, improving the cold tolerance of rice is vital for ensuring food security. In this study, a new cold tolerance-related QTL in rice (qPSR7-2) was detected on chromosome 7 following a genome-wide association study involving 173 japonica rice germplasm resources. The fine mapping of this locus identified Os07g0541800 as a candidate gene associated with qPSR7-2. This gene encodes a cysteine-rich receptor-like kinase. The functional verification of Os07g0541800 involving transgenic plants indicated that qPSR7-2 positively regulates rice cold tolerance at the seedling stage. The examination of the cold tolerance of 984 germplasm resources from the 3000 Rice Genomes Project at the seedling stage and their respective haplotypes at qPSR7-2 revealed that the proportion of favorable haplotypes in germplasm resources increased as the latitude increased. More than 90% of the rice varieties cultivated in Europe and Japan appear to carry qPSR7-2, implying that qPSR7-2 may mediate the acclimation of rice to low-temperature stress. The findings of this study will further clarify the molecular networks regulating rice cold tolerance, while also providing researchers and breeders with new genetic resources and information relevant for developing cold-tolerant rice varieties.