敲除TaMAPK1部分同源基因对小麦苗期耐旱性的调控机制OA

To elucidate the functions of the wheat mitogen-activated protein kinase genes TaMAPK1-6A,TaMAPK1-6B,and TaMAPK1-6Din seedling drought tolerance and the additive effects among these homeologous genes,this study utilized the spring wheat cultivar Fielder and its CRISPR/Cas9 media-ted single-gene mutants-mapk1-aa,mapk1-bb,and mapk1-dd-generated in the Fielder genetic back-ground.Through hybridization,self-pollination,and genotyping of segregating progeny,double-gene knockout mutants and triple-gene knockout homozygous mutants(hereafter referred to as double and triple mutants)were successfully developed.The drought tolerance at the seedling stage was system-atically evaluated for these single,double,and triple mutants,along with the wild-type Fielder con-trol.The results demonstrated that loss-of-function mutations in single TaMAPK1 genes significantly reduced drought tolerance in wheat seedlings,manifested as decreased leaf water retention,reduced accumulation of osmotic adjustment substances,and enhanced membrane lipid peroxidation.Further investigation revealed that drought tolerance was further impaired in double and triple mutants,with the deterioration of physiological and biochemical indicators intensifying as the number of mutated gene copies increased.In summary,the TaMAPK1 gene positively regulates drought tolerance at the wheat seedling stage,and its homeologous genes exhibit cumulative regulatory effects.