A sucrose non-fermenting-1-related protein kinase-1 gene, IbSnRK1, confers salt, drought and cold tolerance in sweet potato

Abstract

Sucrose non-fermenting-1-related protein kinase-1 (SnRK1) regulates carbon and nitrogen metabolism in plants. However, its roles and their underlying mechanisms in tolerance to abiotic stresses are little known. The present study indicated that the IbSnRK1 gene was strongly induced by NaCl, polyethylene glycol (PEG) 6000, hydrogen peroxide (H2O2), cold (4 °C), and abscisic acid (ABA). Its overexpression significantly increased salt, drought, and cold tolerance in transgenic sweet potato plants. ABA, proline, and K+ contents were significantly increased, whereas malondialdehyde (MDA), Na+ and H2O2 contents and O2− production rate were significantly decreased in the transgenic plants under salt, drought, and cold stresses. Overexpression of the gene up-regulated genes involved in ABA biosynthesis, stress response, and stomatal closure; increased enzyme activities in the reactive oxygen species (ROS) scavenging system; and controlled stomatal closure under salt, drought, and cold stresses. These results show that the IbSnRK1 gene confers salt, drought, and cold tolerance in sweet potato by activating the ROS scavenging system and controlling stomatal closure via the ABA signaling pathway.