miR2119, a Novel Transcriptional Regulator, Plays a Positive Role in Woody Plant Drought Tolerance by Mediating the Degradation of the Gene Associated with Apoptosis.

, an important vegetation restoration species with economic and ecological benefits in the arid region of northwest China, is characterized by significant drought tolerance. However, the underlying molecular mechanisms by which miRNAs confer this trait in are unclear. Here, we investigate the effect of CkmiR2119 on drought tolerance and identified its target gene, . A negative correlation of CkmiR2119 and in both stems and leaves in a drought gradient treatment followed by target gene validation suggest that CkmiR2119 might negatively regulate . Consistently, a decrease in the expression of the gene was observed after both transient transformation and stable transformation of CkamiR2119 in tobacco (). Moreover, the physiological analysis of CkamiR2119 and transgenic plants further indicate that CkmiR2119 can enhance the drought tolerance of in two aspects: (i) downregulating expression to accelerate vessel maturation in stems; (ii) contributing to a higher level of in mesophyll cells to inhibit programmed cell death (PCD). This work reveals that CkmiR2119 can increase plants' drought tolerance by downregulating the expression of , providing a theoretical basis to improve plants' ability to withstand stress tolerance by manipulating miRNAs.