Reactive electrophile species activate defense gene expression in Arabidopsis

Abstract

SummaryCompounds containing a,b-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 a,b-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.

Accumulation of 9- and 13-KODEs in response to jasmonic acid treatment and pathogenic infection in rice

“…33) The induction of stress responses by treatments with α, β-unsaturated carbonyl compounds has been reported in many other plant species. [42][43][44][45] In the present study, however, treatments with acrolein, β-ionone, 2,4-hexadienal, 2-hepten-2-one, and C 4 -C 10 aldehydes with a double bond at their α position only marginally induced sakuranetin and naringenin although 2,4-hexadienal and 2-hepten-2-one induced the accumulation of serotonin to levels close to those induced by 13-KODE treatment. The presence of an α, β-unsaturated carbonyl group in the molecular structure is therefore insufficient for the induction of defensive secondary metabolites in rice.…”

Biotic and heavy metal stress response in plants: evidence for common signals

“…For the example just described, candidates for such compounds might be fatty acid metabolites which contain electrophilic a; b-unsaturated carbonyl groups as structural feature as suggested by Farmer and colleagues ( Fig. 1) [21,26]. Remarkably, 12-oxo-phytodienoic acid belongs to this type of oxylipins.…”

Acrolein, an α,β-Unsaturated Carbonyl, Inhibits Both Growth and PSII Activity in the CyanobacteriumSynechocystissp. PCC 6803

“…Comprehensive analysis of carbonyls was conducted by the method of Matsui et al (2009), with slight modifications. 23,46) S. 6803 cells (65 mg, Chl equivalent) was homogenized in 500 mL, acetonitrile containing 5 nmol 2-ethylhexanal (as internal standard) and 0.005% (w/v) butylhydroxytoluene, and then incubated at 60 C for 30 min. After 400 mL of the extract was collected in another tube, 2,4-dinitrophenylhydrazine (final concentration of 0.5 mM) and formic acid (final concentration 0.5 M) were added.…”

“…[20][21][22] These are highly reactive in plant cells. [23][24][25][26][27] Cell damage due to attacks by sugar-derived RCs and , -unsaturated carbonyls produced by the auto-oxidation of sugars has been termed plant diabete. 28) Vertebrates possess detoxification systems, e.g., the glyoxalase system and aldo-keto reductase (AKR), to remove sugar-derived RCs.…”

“…A. thaliana plants express NADPH-dependent alkenal/one oxidoreductase (AOR), which reduces , -unsaturated carbonyls. 22,23) AOR has been found to function in the detoxification of , -unsaturated carbonyls in plants that suffer methyl viologen-induced oxidative stress. 23) These results indicate that both sugar-derived RCs and , -unsaturated carbonyls are produced and accumulate, and that scavenging of them is essential for plant growth.…”