AcCNGC2 Enhances the Tolerance of Transgenic Nicotiana benthamiana to Low Temperature and Drought

Cyclic nucleotide‐gated ion channels (CNGCs) are membrane channel proteins of calcium ions, which participate in biotic and abiotic stress responses in plants. This study focused on the function of cyclic nucleotide‐gated ion channels (CNGCs) in plant stress response, taking onion AcCNGC2 gene as the research object. The encoded protein contains conserved cyclic nucleotide‐binding domain (CNBD) and calmodulin‐binding domain (CaMBD), and its expression was significantly induced by both low‐temperature and drought stress. The overexpression vector of AcCNGC2 was constructed and transformed to Nicotiana benthamiana . The analysis of stress phenotypes showed that under 24 h of drought and low‐temperature treatment, the overexpressed lines maintained normal growth, while the wild‐type plants were irreversibly damaged and wilted seriously. Further detection of physiological indexes showed that the relative conductivity and malondialdehyde content of overexpressed strains were significantly lower than those of wild type, and the chlorophyll content was significantly higher than that of wild type. These results confirmed that AcCNGC2 significantly enhanced the tolerance of plants to low‐temperature and drought stress by reducing membrane lipid peroxidation damage and maintaining the stability of photosynthetic system.