Yanfei Zhang*, Jingyi Wang*, Yuying Li*, Zihui Zhang*, Lili Yang, Min Wang, Yining Zhang, Jie Zhang, Chaonan Li, Long Li, Matthew P Reynolds, Ruilian Jing, Chenyang Wang†, Xinguo Mao†

Plant Physiology, 2022, IF: 8.005

DOI: 10.1093/plphys/kiac523

Abstract

Wheat ( Triticum aestivum ) is particularly susceptible to water deficit at the jointing stage of its development. Sucrose non-fermenting 1-related protein kinase 2 (SnRK2) acts as a signaling hub in the response to drought stress, but whether SnRK2 helps plants cope with water deficit via other mechanisms is largely unknown. Here, we cloned and characterized  TaSnRK2.10 , which was induced by multiple abiotic stresses and phytohormones. Ectopic expression of  TaSnRK2.10  in rice ( Oryza sativa ) conferred drought tolerance, manifested by multiple improved physiological indices, including increased water content, cell membrane stability, and survival rates, as well as decreased water loss and accumulation of H₂O₂ and malonaldehyde. TaSnRK2.10 interacted with and phosphorylated early responsive to dehydration 15 (TaERD15) and enolase 1 (TaENO1)  in vivo  and  in vitro . TaERD15 phosphorylated by TaSnRK2.10 was prone to degradation by the 26S proteasome, thereby mitigating its negative effects on drought tolerance. Phosphorylation of TaENO1 by TaSnRK2.10 may account for the substantially increased levels of phosphoenolpyruvate (PEP), a key metabolite of primary and secondary metabolism, in  TaSnRK2.10 -overexpressing rice, thereby enhancing its viability under drought stress. Our results demonstrate that TaSnRK2.10 not only regulated stomatal aperture and the expression of drought-responsive genes, but also enhanced PEP supply and promoted the degradation of TaERD15, all of which enhanced drought tolerance.