The TaPUB1-TabZIP9L-TaLEA3 Module Positively Regulates Drought Tolerance by Mediating Stomatal Closure and Antioxidant Ability in Wheat.

Wheat yield is increasingly constrained by drought stress. Post-translational modifications, particularly ubiquitination, are essential for plant adaptation to abiotic stresses. This study demonstrates that TaPUB1 overexpression substantially enhances drought tolerance, whereas RNAi lines display markedly higher sensitivity. TaPUB1-overexpressing lines showed higher photosynthetic efficiency and increased redox enzyme activities, leading to reduced ROS accumulation. TaPUB1 specifically interacts with TabZIP9L, a negative regulator of drought responses, and mediates its ubiquitination to modulate protein stability. TabZIP9L knockout increases drought tolerance by elevating antioxidant enzyme activity. Moreover, TabZIP9L directly binds TaLEA3 promoter elements and suppresses its transcription. TaLEA3 overexpression further enhances drought resistance through improved stomatal closure and antioxidant capacity. Together, these findings indicate that TaPUB1 improves wheat drought tolerance through the TaPUB1-TabZIP9L-TaLEA3 regulatory module.