Regulation of Stomatal Immunity by Interdependent Functions of a Pathogen-Responsive MPK3/MPK6 Cascade and Abscisic Acid
Activation of mitogen-activated protein kinases (MAPKs) is one of the earliest responses after plants sense an invading pathogen. Here, we show that MPK3 and MPK6, two Arabidopsis thaliana pathogen-responsive MAPKs, and their upstream MAPK kinases, MKK4 and MKK5, are essential to both stomatal and a...
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Published in | The Plant cell Vol. 29; no. 3; pp. 526 - 542 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
American Society of Plant Biologists
01.03.2017
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Subjects | |
Online Access | Get full text |
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Summary: | Activation of mitogen-activated protein kinases (MAPKs) is one of the earliest responses after plants sense an invading pathogen. Here, we show that MPK3 and MPK6, two Arabidopsis thaliana pathogen-responsive MAPKs, and their upstream MAPK kinases, MKK4 and MKK5, are essential to both stomatal and apoplastic immunity. Loss of function of MPK3 and MPK6, or their upstream MKK4 and MKK5, abolishes pathogen/microbe-associated molecular pattern- and pathogen-induced stomatal closure. Gain-of-function activation of MPK3/MPK6 induces stomatal closure independently of abscisic acid (ABA) biosynthesis and signaling. In contrast, exogenously applied organic acids such as malate or citrate are able to reverse the stomatal closure induced by MPK3/MPK6 activation. Gene expression analysis and in situ enzyme activity staining revealed that malate metabolism increases in guard cells after activation of MPK3/MPK6 or inoculation of pathogen. In addition, pathogen-induced malate metabolism requires functional MKK4/MKK5 and MPK3/MPK6. We propose that the pathogen-responsive MPK3/MPK6 cascade and ABA are two essential signaling pathways that control, respectively, the organic acid metabolism and ion channels, two main branches of osmotic regulation in guard cells that function interdependently to control stomatal opening/closure. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 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.plantcell.org) is: Juan Xu (xujuan@zju.edu.cn). www.plantcell.org/cgi/doi/10.1105/tpc.16.00577 Current address: School of Medicine, University of Missouri, Kansas City, MO 64108. |
ISSN: | 1040-4651 1532-298X |
DOI: | 10.1105/tpc.16.00577 |