Identification and functional analysis of low temperature responsive genes ZmNTL1 and ZmNTL5 in maize

Under low temperature stress, the ion leakage rate in the leaves of zmntl1zmntl5 was significantly higher than in the wild-type B104. The fresh and dry weights of both aboveground and belowground tissues, as well as chlorophyll content, were significantly lower in zmntl1zmntl5 compared to B104. In contrast, zmntl1zmntl5 exhibited significantly higher levels of O2܋ and H2O2, while the activities of antioxidant enzymes GST, SOD, POD, and CAT were significantly reduced.

Furthermore, the expression levels of ZmGST24, ZmNCED3, ZmDREB1.6, and ZmDREB2A were markedly decreased in zmntl1zmntl5 compared to B104 under cold stress. In summary, the absence of ZmNTL1 and ZmNTL5 compromises cold tolerance in maize, suggesting that both genes function as positive regulators in the cold stress response. This study provides a valuable theoretical foundation and genetic resources for the improvement of cold-tolerant maize varieties and the development of new cultivars.