A novel Populus euphratica DUB gene, PeMINDY3, enhances drought and salt tolerance by promoting ROS scavenging

Deubiquitinating enzymes (DUBs) are essential for plant responses to abiotic stress. However, the function of these genes in Populus euphratica, an ideal woody plant species for investigating abiotic stress response mechanisms, is largely unknown. In our previous study, a novel DUB gene, PeMINDY3, was revealed to contribute to the resistance of seeds to salinity stress. In the current study, PeMINDY3 was cloned and functionally characterized. A phylogenetic analysis indicated PeMINDY3 belongs to the MINDY subfamily of DUBs. Subcellular localization results showed that PeMINDY3 is located in chloroplasts. According to the qRT-PCR and GUS staining analyses, PeMINDY3 expression was induced in response to drought and high salinity treatment. The ectopic expression of PeMINDY3 in Arabidopsis thaliana increased the tolerance to drought and salt stress. Moreover, compared with the wild-type (WT) plants, A. thaliana plants ectopically expressing PeMINDY3 had longer primary roots and higher fresh weights, relative water contents, and antioxidant enzyme activities, but lower relative electrical conductivities. Additionally, stress-related genes were more highly expressed in the PeMINDY3 ectopically expressing plants than in the WT plants after the abiotic stress treatments. Furthermore, yeast one-hybrid and luciferase assays identified PeRAV2 as a regulator of PeMINDY3 expression. These findings suggest that PeMINDY3 positively modulates drought and salt stress tolerance, providing a foundation for further exploration of the function of DUB.