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Spermine signalling in tobacco: activation of mitogen‐activated protein kinases by spermine is mediated through mitochondrial dysfunction
Author(s) -
Takahashi Yoshihiro,
Berberich Thomas,
Miyazaki Atsushi,
Seo Shigemi,
Ohashi Yuko,
Kusano Tomonobu
Publication year - 2003
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.2003.01923.x
Subject(s) - kinase , mitogen activated protein kinase , spermine , protein kinase a , mapk/erk pathway , microbiology and biotechnology , downregulation and upregulation , signal transduction , biochemistry , chemistry , biology , enzyme , gene
Summary Polyamines (PAs) play important roles in cell proliferation, growth and environmental stress responses of all living organisms. In this study, we examine whether these compounds act as signal mediators. Spermine (Spm) specifically activated protein kinases of tobacco leaves, which were identified as salicylic acid (SA)‐induced protein kinase (SIPK) and wound‐induced protein kinase (WIPK), using specific antibodies. Upon Spm treatment, upregulation of WIPK , but not SIPK , was observed. Spm‐induced mitogen‐activated protein kinases (MAPKs) activation and WIPK upregulation were prevented upon pre‐treatment with antioxidants and Ca 2+ channel blockers. Additionally, Spm specifically stimulated expression of the alternative oxidase ( AOX ) gene, which was disrupted by these antioxidants and Ca 2+ channel blockers. Bongkrekic acid (BK), an inhibitor of the opening of mitochondrial permeability transition (PT) pores, suppressed MAPKs activation and accumulation of WIPK and AOX mRNA. Our data collectively suggest that Spm causes mitochondrial dysfunction via a signalling pathway in which reactive oxygen species and Ca 2+ influx are involved. As a result, the phosphorylation activities of the two MAPK enzymes SIPK and WIPK are stimulated.