Reactive short-chain leaf volatiles act as powerful inducers of abiotic stress-related gene expression

Abiotic stresses cause serious damage to plants; therefore, plants undergo a complicated stress response through signal transduction originating from environmental stimuli. Here we show that a subset of short-chain leaf volatiles with an alpha, beta-unsaturated carbonyl bond in their structure (reactive short-chain leaf volatiles, RSLVs) like (E)-2-hexenal and (E)-2-butenal can act as signal chemicals that strongly induce the gene expression of abiotic-related transcription factors, such as heat stress-related transcription factors (HSFA2, MBF1c) and other abiotic stress-related transcription factors (DREB2A, ZATs). RSLV-induced expression of HSFA2 and MBF1c was eliminated in HSFA1s-, known as heat stress response master regulators, knockout mutant, whereas those of DREB2A and ZATs were not, suggesting that the RSLV signaling pathway is composed of HSFA1-dependent and -independent pathways. RSLV treatment induced production of chaperon proteins, and the RSLV-treated Arabidopsis thus demonstrated enhanced abiotic stress tolerance. Because oxidative stress treatment enhanced RSLV production, we concluded that commonly found RSLVs produced by environmental stresses are powerful inducer of abiotic stress-related gene expression as oxidative stress signals.