Signal Transduction Pathway of Al Responsive Malate Release in Arabidopsis-Involvement of Reversible Protein Phosphorylation and STOP1 Transcription Factor

摘要

Arabidopsis releases malate from the roots in response to aluminum, which is specific to Al and not elicited by other rhizotoxic ions. The malate release was activated by Al and concomitant with increased expression of the AtALMT1 gene, an Arabidopsis homologue of the wheat Al-activated malate transporter TaALMT1. Pharmacological treatments indicate that AtALMT1 system is regulated by both transcriptional and post-transcriptional processes downstream of reversibly phosphorylated proteins. A mutant study indicated that activation of AtALMT1 transcription requires a Cys2-Hys2 zinc finger transcription factor, STOP1 (Sensitive to Proton rhizotoxicity 1) , which is essential for both Al3+ and H+ tolerances of Arabidopsis.