BoMYC2 and BoAREB1 Interact With BoMYB2 to Respond to ABA Signaling and Drought Stress in Cabbage

The MYB family has been extensively studied in model organisms, but research on these transcription factors in vegetable crops such as cabbage (Brassica oleracea L. var. capitata L.) remains incomplete. We cloned BoMYB2 and determined its role in cabbage drought response. We found that overexpression of BoMYB2, which is induced by ABA, significantly enhanced cabbage tolerance to drought, whereas BoMYB2-silenced line displayed the opposite phenotype. Two proteins that interact with BoMYB2, BoMYC2 and BoAREB1, were verified by yeast two-hybrid, luciferase complementation, pull-down assays. Overexpression of these genes in Arabidopsis thaliana significantly improved drought tolerance in A. thaliana, while their transient silencing in cabbage seedlings reduced drought tolerance. Both proteins are also induced by ABA, and they cooperate with BoMYB2 to enhance plant antioxidant capacity under drought, modulate downstream gene expression, and increase plant survival during water deficit. In summary, our results indicate that BoMYB2-BoMYC2 and BoMYB2-BoAREB1 complexes play important roles in ABA-signal-mediated regulation of drought responses in cabbage.