Overexpression of PcNAC2 from Poa crymophila significantly enhances plant tolerance to chilling, salinity and osmotic stresses.

BACKGROUND: Poa crymophila is a perennial herbaceous plant of the Poaceae family that is adapted to high-altitude environments of Qinghai-Tibet Plateau, exhibiting outstanding cold and drought tolerance. Transcriptomic analyses have indicated that the transcription factor gene CL14612.Contig2_DB in P. crymophila is significantly upregulated in response to both low-temperature and drought stress. RESULTS: Genomic and homology analysis has identified CL14612.Contig2_DB as the transcription factor PcNAC2, which has a total gene length of 1084 bp with a coding sequence of 981 bp, including one intron and two exons. To elucidate its function, we cloned PcNAC2 cDNA and introduced it into tobacco plants (Nicotiana tabacum and Nicotiana benthamiana). The results demonstrated that the heterologous expression of PcNAC2 markedly enhanced the tolerance to chilling, freezing, osmotic, and salt stress in the transgenic tobacco. Under stress conditions, the transgenic tobacco exhibited more developed root systems and superior growth compared to wild-type plants, and was able to recover rapidly after stress relief. CONCLUSIONS: This study presents the pivotal role of PcNAC2 in mediating multiple abiotic stress responses and provides a valuable genetic resource for the breeding of stress-tolerance forage grasses or other crops in high-altitude environments.