Tyrosylprotein sulfotransferase suppresses ABA signaling via sulfation of SnRK2.2/2.3/2.6

Phytohormone abscisic acid(ABA)plays vital roles in stress tolerance,while long-term overactivation of ABA signaling suppresses plant growth and development.However,the braking mechanism of ABA responses is not clear.Protein tyrosine sulfation catalyzed by tyrosylprotein sulfotransferase(TPST)is a critical post-translational modification.Through genetic screening,we identified a tpst mutant in Arabidopsis that was hypersensitive to ABA.In-depth analysis revealed that TPST could interact with and sulfate SnRK2.2/2.3/2.6,which accelerated their degradation and weakened the ABA signaling.Taken together,these findings uncovered a novel mechanism of desensitizing ABA responses via protein sulfation.