RtNAC055 promotes drought tolerance via a stomatal closure pathway linked to methyl jasmonate/hydrogen peroxide signaling in .

The stomata regulate CO uptake and efficient water usage, thereby promoting drought stress tolerance. NAC proteins (NAM, ATAF1/2, and CUC2) participate in plant reactions following drought stress, but the molecular mechanisms underlying NAC-mediated regulation of stomatal movement are unclear. In this study, a novel NAC gene from , , was found to enhance drought tolerance via a stomatal closure pathway. It was regulated by RtMYC2 and integrated with jasmonic acid signaling and was predominantly expressed in stomata and root. The suppression of could improve jasmonic acid and HO production and increase the drought tolerance of transgenic callus. Ectopic expression of in the mutant rescued its drought-sensitive phenotype by decreasing stomatal aperture. Under drought stress, overexpression of in poplar promoted ROS (HO) accumulation in stomata, which accelerated stomatal closure and maintained a high photosynthetic rate. Drought upregulated the expression of , , and ., as well as antioxidant enzyme activities in heterologous expression poplars. RtNAC055 promoted HO production in guard cells by directly binding to the promoter of , thus regulating stomatal closure. The stress-related genes . were directly regulated by RtNAC055. These results indicate that RtNAC055 regulates stomatal closure by maintaining the balance between the antioxidant system and HO level, reducing the transpiration rate and water loss, and improving photosynthetic efficiency and drought resistance.