title: Reactive electrophile species activate defense gene expression in Arabidopsis.
abstract: Compounds containing alpha,beta-unsaturated carbonyl groups are increasingly implicated as potent regulators of gene expression; some are powerful cytotoxins known to accumulate at the site of lesion formation in host-pathogen interactions. We used a robust measurement of photosynthetic efficiency to quantify the toxicity of a variety of lipid derivatives in Arabidopsis leaves. Small alpha,beta-unsaturated carbonyl compounds (e.g. acrolein and methyl vinyl ketone) were highly active and proved to be potent stimulators of expression of the pathogenesis-related gene HEL (PR4). These small volatile electrophiles were far more active than larger alkenal homologs like 2(E)-hexenal, and activated HEL expression in a manner independent of salicylate, ethylene, and jasmonate production/perception. Electrophile treatment massively increased the levels of unesterified cyclopentenone jasmonates, which themselves are electrophiles. Patterns of gene expression in response to electrophile treatment and in response to avirulent bacteria were compared, which revealed strikingly similar transcript profiles. The results broaden the range of known biologic effects of reactive electrophile species to include the activation of a pathogenesis-related gene (HEL) and genes involved in metabolism. Electrophiles can act as mediators of both genetic and biochemical effects on core defense signal transduction.
authors.affiliation: Gene Expression Laboratory, University of Lausanne, Biology Building, Switzerland.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Alméras
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Stolz
authors.forename: Sabine
authors.initials: S
authors.lastname: Vollenweider
authors.forename: Philippe
authors.initials: P
authors.lastname: Reymond
authors.forename: Laurent
authors.initials: L
authors.lastname: Mène-Saffrané
authors.forename: Edward E
authors.initials: EE
authors.lastname: Farmer
mesh_terms: D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics* / Q000382:microbiology; D005453:Fluorescence; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D006360:Heat-Shock Proteins / Q000378:metabolism; D008055:Lipids / Q000494:pharmacology* / Q000633:toxicity; D010788:Photosynthesis / Q000187:drug effects; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics / Q000382:microbiology; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors
chemical_list: D006360:Heat-Shock Proteins; D008055:Lipids; D045322:Photosynthetic Reaction Center Complex Proteins