Green leaf volatile (Z)-3-hexeny-1-yl acetate reduces salt stress in peanut by affecting photosynthesis and cellular redox homeostasis.

Green leaf volatiles (GLVs) are released by plants when they encounter biotic stress, but their functions in the response to abiotic stress have not been determined. We have previously shown that exogenous application of (Z)-3-hexeny-1-yl acetate (Z-3-HAC), a kind of GLV, could alleviate salt stress in peanut (Arachis hypogaea L.) seedlings; however, notably little is known concerning the transcription regulation mechanisms of Z-3-HAC. In this study, we comprehensively characterized the transcriptomes and physiological indices of peanut seedlings exposed to Z-3-HAC and/or salt stress. Analysis of transcriptome data showed that 1420 genes were upregulated in the seedlings primed with Z-3-HAC under salt stress compared with the non-primed treatment. Interestingly, these genes were significantly enriched in the photosynthetic and ascorbate metabolism-related categories, as well as several plant hormone metabolism pathways. The physiological data revealed that Z-3-HAC significantly increased the net photosynthetic rate, SPAD value, plant height and shoot biomass compared with the non-primed peanut seedlings under salt stress. A significantly higher ratio of K+ :Na+ , reduced-to-oxidized glutathione (GSH:GSSG), and ascorbate-to-dehydroascorbate (AsA:DHA) were also observed for the plants primed with Z-3-HAC compared with the salt stress control. Meanwhile, Z-3-HAC significantly increased the activity of enzymes in the AsA-GSH cycle. Taken together, these results highlight the importance of Z-3-HAC in protecting peanut seedlings against salt stress by affecting photosynthesis, cellular redox homeostasis, K+ :Na+ homeostasis, and phytohormones.