Overexpression of a protein kinase gene MpSnRK2.10 from Malus prunifolia confers tolerance to drought stress in transgenic Arabidopsis thaliana and apple.

Members of the sucrose non-fermenting-1-related protein kinase 2 (SnRK2) family play central roles in the abscisic acid (ABA) signaling pathway and in mediating osmotic stress signaling and tolerance in plants. Previously, 12 full-length coding sequences that belong to SnRK2 gene family were identified and cloned in wild apple species Malus prunifolia. In this study, one of the members, MpSnRK2.10, was overexpressed in Arabidopsis and apple to investigate its potential function in response to drought stress. The results showed that overexpression of this gene did not affect plant growth under normal conditions. However, the transgenic plants showed enhanced tolerance to drought, as indicated by the amelioration in phenotype appearance and physiological indices related to drought stress damage. Additionally, transgenic apple plants overexpressing MpSnRK2.10 exhibited greater sensitivity to ABA compared to wild-type (WT) plants. Moreover, expressions of three stress response genes, MdRAB18, MdRD22, and MdRD29B, were more strongly induced in transgenic apple plants than in the WT when subjected to ABA and mannitol treatments. Taken as a whole, our study suggests that MpSnRK2.10 has a role in the enhancement of ABA signal transduction in response to stress, and that the manipulation of MpSnRK2.10 expression could be a feasible approach for improving abiotic stress tolerance in apple and other important crops.