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First published online January 12, 2007; 10.1104/pp.106.091298 Plant Physiology 143:1398-1407 (2007) © 2007 American Society of Plant Biologists OPEN ACCESS ARTICLE
The coronatine-insensitive 1 Mutation Reveals the Hormonal Signaling Interaction between Abscisic Acid and Methyl Jasmonate in Arabidopsis Guard Cells. Specific Impairment of Ion Channel Activation and Second Messenger Production1,[OA]Graduate School of Natural Science and Technology, Okayama University, Tsushima-Naka, Okayama 7008530, Japan (S.M., Y.N., Y.S., Y.M.); Research Institute for Biological Sciences OKAYAMA, Kibichuo-cho, Okayama 7161241, Japan (K.O.); and Department of Agriculture, Okayama University, Tsushima-Naka, Okayama 7008530, Japan (M.W.-S.)
Methyl jasmonate (MeJA) elicits stomatal closing similar to abscisic acid (ABA), but whether the two compounds use similar or different signaling mechanisms in guard cells remains to be clarified. We investigated the effects of MeJA and ABA on second messenger production and ion channel activation in guard cells of wild-type Arabidopsis (Arabidopsis thaliana) and MeJA-insensitive coronatine-insensitive 1 (coi1) mutants. The coi1 mutation impaired MeJA-induced stomatal closing but not ABA-induced stomatal closing. MeJA as well as ABA induced production of reactive oxygen species (ROS) and nitric oxide (NO) in wild-type guard cells, whereas MeJA did not induce production of ROS and NO in coi1 guard cells. The experiments using an inhibitor and scavengers demonstrated that both ROS and NO are involved in MeJA-induced stomatal closing as well as ABA-induced stomatal closing. Not only ABA but also MeJA activated slow anion channels and Ca2+ permeable cation channels in the plasma membrane of wild-type guard cell protoplasts. However, in coi1 guard cell protoplasts, MeJA did not elicit either slow anion currents or Ca2+ permeable cation currents, but ABA activated both types of ion channels. Furthermore, to elucidate signaling interaction between ABA and MeJA in guard cells, we examined MeJA signaling in ABA-insensitive mutant ABA-insensitive 2 (abi2-1), whose ABA signal transduction cascade has some disruption downstream of ROS production and NO production. MeJA also did not induce stomatal closing but stimulated production of ROS and NO in abi2-1. These results suggest that MeJA triggers stomatal closing via a receptor distinct from the ABA receptor and that the coi1 mutation disrupts MeJA signaling upstream of the blanch point of ABA signaling and MeJA signaling in Arabidopsis guard cells.
1 This work was supported by the Ministry of Education, Culture, Sports, Science and Technology of Japan (grants for Scientific Research on Priority Areas to Y.M.). The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Yoshiyuki Murata (muta{at}cc.okayama-u.ac.jp). [OA] Open Access articles can be viewed online without a subscription. www.plantphysiol.org/cgi/doi/10.1104/pp.106.091298 * Corresponding author; e-mail muta{at}cc.okayama-u.ac.jp; fax 81862518388. Received October 12, 2006; accepted December 28, 2006; published January 12, 2007. This article has been cited by other articles:
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