Salicylic acid-independent induction of pathogenesis-related gene expression by fusicoccin.
Treatment of tomato plants (Lycopersicon esculentum Mill.) with fusicoccin (FC), an activator of the plasma-membrane H+-ATPase which maintains an electrochemical gradient across the plasma membrane, resulted in a dose-dependent accumulation of transcripts for intra- and extracellular pathogenesis-related (PR) proteins. The accumulation of PR protein transcripts was paralleled by an increase in leaf salicylic acid (SA) content. Transcripts of PR proteins and SA started to accumulate 3 h after FC treatment. 2-Aminoindan-2-phosphonic acid, an inhibitor of SA synthesis, was used to assess the role of SA in FC-mediated induction of PR gene expression. 2-Aminoindan-2-phosphonic acid was found to suppress the accumulation of SA but not the induction of PR gene expression in response to FC treatment. Furthermore, in transgenic tobacco plants overexpressing a bacterial salicylate hydroxylase gene (nahG-tobacco), PR transcripts accumulated after FC treatment to levels similar to those observed in control tobacco plants. The data indicate a role for the proton gradient across the plasma membrane in the SA-independent induction of PR gene expression.
Schaller
A
A
Institute of Plant Sciences, ETH-Zürich, Switzerland. andreas.schaller@ipw.biol.ethz.ch
Roy
P
P
Amrhein
N
N
D006027:Glycosides / Q000494:pharmacology*; D007189:Indans; D018551:Solanum lycopersicum / Q000235:genetics / Q000378:metabolism*; D063065:Organophosphonates / Q000494:pharmacology; D030821:Plants, Genetically Modified / Q000378:metabolism; D018749:RNA, Plant / Q000096:biosynthesis* / Q000378:metabolism; D020156:Salicylic Acid / Q000037:antagonists & inhibitors / Q000378:metabolism*
C411146:2-aminoindan-2-phosphonic acid; D006027:Glycosides; D007189:Indans; D063065:Organophosphonates; D018749:RNA, Plant; C007808:fusicoccin; D020156:Salicylic Acid