Induction of wound response gene expression in tomato leaves by ionophores.
Three ionophores were used to investigate a potential role of the plasma-membrane (PM) potential in the regulation of systemic wound-response gene expression in tomato (Lycopersicon escuilentum Mill.) plants. Valinomycin, nigericin, and gramicidin, which affect the PM potential by dissipating H+ and K+ gradients, respectively, induced the rapid accumulation of wound-response gene transcripts. Transcript induction by gramicidin was kinetically, qualitatively and quantitatively similar to systemin-induced transcript accumulation. On a molar basis, gramicidin and nigericin, which affect gradients of both H+ and K+, were more effective than the K+-selective valinomycin. Hyperpolarization of the PM by fusicoccin, on the other hand, repressed wound-response gene expression and, at the same time, induced salicylic acid (SA) accumulation and the expression of pathogenesis-related proteins. We show here that the inhibition of the wound response after fusicoccin treatment is not mediated by elevated concentrations of SA but is likely a direct effect of PM hyperpolarization. The data indicate a role for the PM potential in the differential regulation of wound and pathogen defense responses.
Schaller
A
A
Institute of Plant Sciences, ETH-Zürich, Switzerland. andreas.schaller@ipw.biol.ethz.ch
Frasson
D
D
D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D006027:Glycosides / Q000494:pharmacology; D006096:Gramicidin / Q000494:pharmacology; D007189:Indans; D007476:Ionophores / Q000494:pharmacology*; D007931:Leucyl Aminopeptidase / Q000096:biosynthesis / Q000235:genetics; D018551:Solanum lycopersicum / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D009550:Nigericin / Q000494:pharmacology; D063065:Organophosphonates / Q000494:pharmacology; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D010940:Plant Proteins / Q000096:biosynthesis* / Q000235:genetics; D011480:Protease Inhibitors / Q000378:metabolism; D012313:RNA / Q000032:analysis; D020156:Salicylic Acid / Q000378:metabolism; D015398:Signal Transduction; D013913:Threonine Dehydratase / Q000096:biosynthesis / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects; D014634:Valinomycin / Q000494:pharmacology
C411146:2-aminoindan-2-phosphonic acid; D006027:Glycosides; D007189:Indans; D007476:Ionophores; D063065:Organophosphonates; D010940:Plant Proteins; D011480:Protease Inhibitors; C034104:proteinase inhibitor II protein, plant; D006096:Gramicidin; D014634:Valinomycin; C007808:fusicoccin; C023578:proteinase inhibitor I (plants); D012313:RNA; D007931:Leucyl Aminopeptidase; D013913:Threonine Dehydratase; D020156:Salicylic Acid; D009550:Nigericin