Involvement of Endogenous Abscisic Acid in Methyl Jasmonate-Induced Stomatal Closure in Arabidopsis

Mohammad Anowar Hossain,Misugi Uraji,Yoshimasa Nakamura,Izumi C Mori,Shintaro Munemasa,Yoshiyuki Murata

doi:10.1104/pp.111.172254

Mohammad Anowar Hossain, Misugi Uraji + Show 4 more

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https://doi.org/10.1104/pp.111.172254

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Journal: Plant Physiology	Publication Date: Mar 14, 2011
Citations: 184	License type: CC BY 4.0

Affiliation: Okayama University

Abstract

In this study, we examined the involvement of endogenous abscisic acid (ABA) in methyl jasmonate (MeJA)-induced stomatal closure using an inhibitor of ABA biosynthesis, fluridon (FLU), and an ABA-deficient Arabidopsis (Arabidopsis thaliana) mutant, aba2-2. We found that pretreatment with FLU inhibited MeJA-induced stomatal closure but not ABA-induced stomatal closure in wild-type plants. The aba2-2 mutation impaired MeJA-induced stomatal closure but not ABA-induced stomatal closure. We also investigated the effects of FLU and the aba2-2 mutation on cytosolic free calcium concentration ([Ca(2+)](cyt)) in guard cells using a Ca(2+)-reporter fluorescent protein, Yellow Cameleon 3.6. In wild-type guard cells, FLU inhibited MeJA-induced [Ca(2+)](cyt) elevation but not ABA-induced [Ca(2+)](cyt) elevation. The aba2-2 mutation did not affect ABA-elicited [Ca(2+)](cyt) elevation but suppressed MeJA-induced [Ca(2+)](cyt) elevation. We also tested the effects of the aba2-2 mutation and FLU on the expression of MeJA-inducible VEGETATIVE STORAGE PROTEIN1 (VSP1). In the aba2-2 mutant, MeJA did not induce VSP1 expression. In wild-type leaves, FLU inhibited MeJA-induced VSP1 expression. Pretreatment with ABA at 0.1 μm, which is not enough concentration to evoke ABA responses in the wild type, rescued the observed phenotypes of the aba2-2 mutant. Finally, we found that in wild-type leaves, MeJA stimulates the expression of 9-CIS-EPOXYCAROTENOID DIOXYGENASE3, which encodes a crucial enzyme in ABA biosynthesis. These results suggest that endogenous ABA could be involved in MeJA signal transduction and lead to stomatal closure in Arabidopsis guard cells.

Highlights

In this study, we examined the involvement of endogenous abscisic acid (ABA) in methyl jasmonate (MeJA)-induced stomatal closure using an inhibitor of ABA biosynthesis, fluridon (FLU), and an ABA-deficient Arabidopsis (Arabidopsis thaliana) mutant, aba2-2
To clarify the involvement of endogenous ABA in MeJA signaling in guard cells, the effect of FLU on ABA- or MeJAinduced stomatal closure was examined in wild-type plants
MeJA-induced stomatal closure was inhibited by FLU, while FLU alone showed no significant effect on stomatal closure (Fig. 1)

Summary

Introduction

We examined the involvement of endogenous abscisic acid (ABA) in methyl jasmonate (MeJA)-induced stomatal closure using an inhibitor of ABA biosynthesis, fluridon (FLU), and an ABA-deficient Arabidopsis (Arabidopsis thaliana) mutant, aba. We found that pretreatment with FLU inhibited MeJA-induced stomatal closure but not ABA-induced stomatal closure in wild-type plants. In wild-type leaves, FLU inhibited MeJA-induced VSP1 expression. We found that in wild-type leaves, MeJA stimulates the expression of 9-CIS-EPOXYCAROTENOID DIOXYGENASE3, which encodes a crucial enzyme in ABA biosynthesis. These results suggest that endogenous ABA could be involved in MeJA signal transduction and lead to stomatal closure in Arabidopsis guard cells. Guard cells respond to a variety of external and internal stimuli such as light, drought, external Ca2+, pathogen attack, and the phytohormones abscisic acid (ABA) and methyl jasmonate (MeJA) and regulate CO2 uptake into leaves for photosynthesis, control of transpirational water loss, and innate immunity (Schroeder et al, 2001; Hetherington and Woodward, 2003; Suhita et al, 2004; Israelsson et al, 2006; Melotto et al, 2006; Munemasa et al, 2007; Shimazaki et al, 2007; Islam et al, 2009, 2010b)

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