CPK28-mediated Ca²⁺ signaling regulates STOP1 localization and accumulation to facilitate plant aluminum resistance.

ABSTRACT: The transcription factor SENSITIVE TO PROTON RHIZOTOXICITY 1 (STOP1) functions as a crucial integrator of plant responses to various stresses, including aluminum (Al) stress. Its stability and accumulation are modulated by stress-specific post-translational mechanisms such as phosphorylation and ubiquitination. However, the upstream signaling mechanisms governing these modifications remain poorly understood. Here, we reveal that Ca²⁺ signaling and Ca²⁺-dependent phosphorylation are essential for Al stress-responsive regulation of STOP1. Al exposure specifically induces rapid, spatio-temporally defined biphasic Ca²⁺ signals in Arabidopsis roots and concomitantly activates the Ca²⁺-dependent kinase CPK28. Al-activated CPK28 phosphorylates STOP1 at

SUBMITTER: Ma Y 

PROVIDER: S-EPMC12141487 | biostudies-literature | 2025 Jun

REPOSITORIES: biostudies-literature