TaSnRK2.4 is a vital regulator in control of thousand-kernel weight and response to abiotic stress in wheat

Sucrose non-fermenting 1-related protein kinase 2(Sn RK2) is a plant-specific serine/threonine kinase involved in response to adverse environmental stimuli. Previous studies showed that Ta Sn RK2.4 was involved in response to abiotic stresses and conferred enhanced tolerance to multiple stresses in Arabidopsis. Further experiments were performed to decipher the underlying mechanisms and discover new functions. The genomic sequences of Ta Sn RK2.4 s locating on chromosome 3 A, 3 B and 3 D were obtained. Sequencing identified one and 13 variations of Ta Sn RK2.4-3 A and Ta Sn RK2.4-3 B, respectively, but no variation was detected in Ta Sn RK2.4-3 D. The markers 2.4 AM1, 2.4 BM1 and 2.4 BM2 were developed based on three variations. Association analysis showed that both Ta Sn RK2.4-3 A and Ta Sn RK2.4-3 B were significantly associated with thousand-kernel weight(TKW), and that SNP3 A-T and SNP3 B-C were favorable alleles for higher TKW. Yeast two-hybrid and split luciferase assays showed that Ta Sn RK2.4 physically interacted with abiotic stress responsive protein Ta LTP3, suggesting that Ta Sn RK2.4 enhanced abiotic stress tolerance by activating Ta LTP3. Our studies suggested that Ta Sn RK2.4 have potential in improving TKW and response to abiotic stress.