The 30th International Conference on Arabidopsis Research (ICAR 2019)

647 / 2019-04-29 13:58:31

Arabidopsis Group XIV Ubiquitin-conjugating Enzymes AtUBC32, AtUBC33 and AtUBC34, along with AtPUB19 U-box E3 Ligase, are Negative Regulators of an ABA-mediated Drought Stress Response.

Arabidopsis thaliana,drought stress,E2 ubiquitin conjugating enzyme,interactions between E2s and E3

Plenary track > Abiotic Stress

AtUBC32, AtUBC33, and AtUBC34 are Arabidopsis group XIV E2 ubiquitin-conjugating enzymes (UBCs). AtUBC32 was previously reported to act as an endoplasmic reticulum-associated protein degradation (ERAD) component. Yeast two-hybrid, in vitro pull-down, and bimolecular fluorescence complementation assays revealed that group XIV E2s interacted with the U-box-type E3 ligase AtPUB19, which negatively regulates an ABA-mediated drought stress response. All three group XIV AtUBCs were co-localized with AtPUB19 to the punctae-like structures on the ER membrane of tobacco leaf cells. atubc32, atubc33, and atubc34 single and atubc32atubc33atubc34 triple loss-of-function mutant plants exhibited increased sensitivity to ABA in terms of stomatal closure as compared to the wild-type plants. They also showed markedly enhanced tolerance to drought stress relative to the wild-type plants. These results suggest that the three homologous group XIV AtUBCs, together with AtPUB19, play a negative role in an ABA-mediated drought stress response in Arabidopsis.