Journal of Agricultural and Food Chemistry · 2021 · 27 citations · 29 references
Tea (<i>Camellia sinensis</i>) is the most popular nonalcoholic beverage worldwide. During cultivation, tea plants are susceptible to herbivores and pathogens, which can seriously affect tea yield and quality. A previous report showed that (<i>Z</i>)-3-hexenol is a potentially efficient defensive substance. However, the molecular mechanism mediating (<i>Z</i>)-3-hexenol signaling in tea plants and the resulting effects on plant defenses remain uncharacterized. To clarify the signaling mechanisms in which (<i>Z</i>)-3-hexenol and light are involved, the gene transcription and metabolite levels were assessed, respectively. This study demonstrated that tea plants rapidly and continuously release (<i>Z</i>)-3-hexen-1-ol in response to an insect infestation. (<i>Z</i>)-3-Hexen-1-ol absorbed by adjacent healthy plants would be converted into three insect defensive compounds: (<i>Z</i>)-3-hexenyl-glucoside, (<i>Z</i>)-3-hexenyl-primeveroside, and (<i>Z</i>)-3-hexenyl-vicianoside identified with laboratory-synthesized standards. Moreover, (<i>Z</i>)-3-hexen-1-ol also activates the synthesis of jasmonic acid to enhance the insect resistance of tea plants. Additionally, a continuous light treatment induces the accumulation of (<i>Z</i>)-3-hexenyl-glycosides. Hence, (<i>Z</i>)-3-hexenol serves as a light-regulated signaling molecule that activates the systemic defenses of adjacent plants. Our study reveals the molecular mechanisms by which biotic and abiotic factors synergistically regulate the signaling functions of herbivore-induced plant volatiles in plants, providing valuable information for future comprehensive analyses of the systemic defense mechanisms in plants.
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