The NAC transcription factor family, which is specific to plants, plays a critical role in responses to low-temperature stress, though its regulatory mechanisms are yet to be fully elucidated. In the present study, the low-temperature-induced gene DgNAC3 was isolated from the chrysanthemum variety 'Jinba'. The open reading frame (ORF) of DgNAC3 spans 1170 base pairs, which translates into a protein composed of 389 amino acids. Cold tolerance is significantly improved in transgenic chrysanthemums through the overexpression of DgNAC3, evidenced by reduced wilting and improved survival rates following low-temperature stress. Under stress conditions, transgenic lines showed decreased malondialdehyde (MDA), hydrogen peroxide (H2O2), and superoxide anion (O2 -) concentrations, alongside significantly elevated activities of catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD). Furthermore, the expression of cold stress-responsive genes, including DgPOD, DgCAT, and DgCu/ZnSOD, increased. These results suggest that DgNAC3 overexpression increases the ability of transgenic lines to scavenge reactive oxygen species (ROS), consequently improving cold stress resistance in chrysanthemums.
Zhang et al. (Mon,) studied this question.