The Myrosinases TGG1 and TGG2 Function Redundantly in Reactive Carbonyl Species Signaling in Arabidopsis Guard Cells

• DOI: 10.1093/pcp/pcaa024
• Publication Date: 2020-03-03T12:18:34Z
• Authors: Mohammad Saidur R...; Toshiyuki Nakamura; Yoshimasa Nakamura; Shintaro Munemasa; Yoshiyuki Murata
• Keywords: Acrolein; EGTA

Abstract Myrosinase (β-thioglucoside glucohydrolase, enzyme nomenclature, EC 3.2.1.147, TGG) is a highly abundant protein in Arabidopsis guard cells, of which TGG1 and TGG2 function redundantly abscisic acid (ABA)- methyl jasmonate-induced stomatal closure. Reactive carbonyl species (RCS) are α,β-unsaturated aldehydes ketones, downstream reactive oxygen (ROS) production the ABA signalling pathway cells. Among RCS, acrolein most reactive, significantly produced ABA-treated To clarify signal ROS production, we investigated responses tgg mutants (tgg1-3, tgg2-1 tgg1-3 tgg2-1) to acrolein. Acrolein induced closure triggered cytosolic alkalization wild type (WT), single mutants, but not double mutants. Exogenous Ca2+ only WT also all Acrolein- Ca2+-induced closures were inhibited by an intracellular acidifying agent, butyrate, chelator, ethylene glycol tetraacetic (EGTA) channel blocker, LaCl3. free calcium concentration ([Ca2+]cyt) elevation cells plants elicited [Ca2+]cyt tgg2-1. Our results suggest that redundantly, between RCS