New allelic variants found in key rice salt‐tolerance genes: an association study

Summary Salt stress is a complex physiological trait affecting plants by limiting growth and productivity. Rice, one of the most important food crops, is rated as salt‐sensitive. High‐throughput screening methods are required to exploit novel sources of genetic variation in rice and further improve salinity tolerance in breeding programmes. To search for genotypic differences related to salt stress, we genotyped 392 rice accessions by Eco TILLING . We targeted five key salt‐related genes involved in mechanisms such as N a + / K + ratio equilibrium, signalling cascade and stress protection, and we found 40 new allelic variants in coding sequences. By performing association analyses using both general and mixed linear models, we identified 11 significant SNP s related to salinity. We further evaluated the putative consequences of these SNP s at the protein level using bioinformatic tools. Amongst the five nonsynonymous SNP s significantly associated with salt‐stress traits, we found a T 67 K mutation that may cause the destabilization of one transmembrane domain in O s HKT 1;5, and a P 140 A alteration that significantly increases the probability of O s HKT 1;5 phosphorylation. The K 24 E mutation can putatively affect S al T interaction with other proteins thus impacting its function. Our results have uncovered allelic variants affecting salinity tolerance that may be important in breeding.