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Melatonin is required for H 2 O 2 ‐ and NO ‐mediated defense signaling through MAPKKK 3 and OXI 1 in A rabidopsis thaliana
Author(s) -
Lee Hyoung Yool,
Back Kyoungwhan
Publication year - 2017
Publication title -
journal of pineal research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 131
eISSN - 1600-079X
pISSN - 0742-3098
DOI - 10.1111/jpi.12379
Subject(s) - melatonin , mapk/erk pathway , signal transduction , innate immune system , microbiology and biotechnology , biology , pseudomonas syringae , kinase , map kinase kinase kinase , protein kinase a , chemistry , immune system , immunology , pathogen , neuroscience
Melatonin influences plant innate immunity through the mitogen‐activated protein kinase ( MAPK ) pathway. However, the most upstream MAPK component in melatonin signaling and the dependence of generation of a reactive oxygen species ( ROS ) burst on melatonin synthesis and signaling remain unclear. In this study, treatment of several mekk (alias mapkkk )‐knockout Arabidopsis mutants with melatonin revealed that the MAPKKK 3 and OXI 1 (oxidative signal‐inducible1) kinases are responsible for triggering melatonin‐induced defense signaling pathways. In addition, melatonin induction upon infection with the avirulent pathogen Pseudomonas syringae DC 3000 (avrRpt2) was independent of H 2 O 2 and NO individually, but dependent on the combination of H 2 O 2 and NO . Moreover, melatonin‐mediated induction of the expression of defense‐related genes, such as PR 1 and ICS 1 , was not altered in the H 2 O 2 ‐deficient rbohD/F ‐knockout mutant cotreated with an NO scavenger, indicating that melatonin functions downstream of the ROS and NO burst. Collectively, the data indicate that melatonin‐mediated induction of an innate immune response requires multiple signaling molecules and activation of MAPKKK 3 and OXI 1, followed by triggering of downstream MAPK cascades, such as MAPK 3 and MAPK 6.