Mango MiNAC2D enhances drought, low temperature, and salt stress tolerance in transgenic plants

The NAC transcription factor family represents a unique class of plant-specific regulators involved in abiotic stress responses. In this study, a MiNAC2D gene was obtained from the mango genome and transcriptome. Subcellular localization confirmed the nuclear localization of MiNAC2D. Expression analysis revealed that its transcript levels were highest in leaves and were significantly upregulated under drought, low temperature, and salt stresses. To investigate its biological function, MiNAC2D was overexpressed in Arabidopsis, tomato, and mango. Transgenic Arabidopsis and tomato plants showed enhanced performance under abiotic stress conditions, including higher seed germination rates, increased root length, and improved survival rates. In addition, transgenic plants displayed significantly reduced leaf damage compared to wild-type (WT) controls. Transcriptome profiling of WT and transgenic mango roots under drought stress identified 145 differentially expressed genes involved in signaling pathways, 14 of which were validated by RT-qPCR. Under salt stress, 92 differentially expressed signaling pathway-related genes were identified, with ten confirmed by RT-qPCR. These results suggest that MiNAC2D may enhance drought tolerance through the abscisic acid (ABA) pathway and improve salt tolerance via mechanisms involving ion homeostasis and the ethylene pathway. Overall, this study demonstrates the role of MiNAC2D in enhancing abiotic stress tolerance and provides a foundation for further exploration of its regulatory network in mango.