A NAC transcription factor, TaNAC5D-2, acts as a positive regulator of drought tolerance through regulating water loss in wheat (Triticum aestivum L.)
Jianhui Ma, Xiaoxiao Tang, Bo Sun, Jituo Wei, Liuyin Ma, Meng Yuan, Daijing Zhang, Yun Shao, Chunxi Li, Kun-Ming Chen and Lina Jiang
Environmental and Experimental Botany
NAC transcription factors play critical roles in regulating drought stress. However, the drought-responsive NAC transcription factors are largely unexplored in wheat. In this study, we isolated a NAC gene, TaNAC5D-2, and characterized the function of TaNAC5D-2 as a positive regulator of drought tolerance. The expression level of TaNAC5D-2 was induced under drought or abscisic acid treatment. Transient expression and transcriptional activity assays showed that TaNAC5D-2 is localized to the nucleus, and the C-terminal region exhibited transcriptional activity. Overexpression of TaNAC5D-2 in Arabidopsis thaliana led to greater drought tolerance, fresh weight and dry weight than wild-type plants, and the water loss was significant inhibited in the leaves of overexpression lines. Conversely, silencing of TaNAC5D-2 in wheat seedlings led to increased water loss and decreased growth compared to control and negative control plants under drought stress. RNA-Seq and RT-qPCR revealed that many Group A PP2C genes were upregulated in the TaNAC5D-2 silenced plants compared to negative control. And silencing TaNAC5D-2 negatively regulate ABA-induced stomatal closure that led to higher water loss. These data suggest that TaNAC5D-2 acts as a drought-responsive regulator, possibly by an abscisic acid-mediated stomatal closure to control water loss under drought condition.