Herbivore-induced plant volatiles (HIPVs) play an important role in insect resistance. As a common HIPV in tea plants (Camellia sinensis), β-ocimene has shown anti-insect function in other plants. However, whether β-ocimene in tea plants also provides insect resistance, and its mechanism of synthesis and emission are unknown. In this study, β-ocimene was confirmed to interfere with tea geometrid growth via signaling. Light was identified as the key factor controlling regular emission of β-ocimene induced by the wounding from tea geometrids. β-Ocimene synthase (CsBOS1) was located in plastids and catalyzed β-ocimene formation in overexpressed tobacco. CsBOS1 expression in tea leaves attacked by tea geometrids showed a day-low and night-high variation pattern, while CsABCG expression involved in volatile emission showed the opposite pattern. These two genes might regulate the regular β-ocimene emission from tea plants induced by tea geometrid attack. This study advances the understanding on HIPV emission and signaling in tea plants.
The sweet potato weevil ( Cylas formicarius (Fab.) (Coleoptera: Brentidae)) is a pest that feeds on sweet potato ( Ipomoea batatas (L.) Lam. (Solanales: Convolvulaceae)), causing substantial economic losses annually. However, no safe and effective methods have been found to protect sweet potato from this pest. Herbivore-induced plant volatiles (HIPVs) promote various defensive bioactivities, but their formation and the defense mechanisms in sweet potato have not been investigated. To identify the defensive HIPVs in sweet potato, the release dynamics of volatiles was monitored. The biosynthetic pathways and regulatory factors of the candidate HIPVs were revealed via stable isotope tracing and analyses at the transcriptional and metabolic levels. Finally, the anti-insect activities and the defense mechanisms of the gaseous candidates were evaluated. The production of ( Z )-3-hexenyl acetate ( z 3HAC) and allo -ocimene was induced by sweet potato weevil feeding, with a distinct circadian rhythm. Ipomoea batatas ocimene synthase (IbOS) is first reported here as a key gene in allo -ocimene synthesis. Insect-induced wounding promoted the production of the substrate, ( Z )-3-hexenol, and upregulated the expression of IbOS , which resulted in higher contents of z 3HAC and allo -ocimene, respectively. Gaseous z 3HAC and allo -ocimene primed nearby plants to defend themselves against sweet potato weevils. These results provide important data regarding the formation, regulation, and signal transduction mechanisms of defensive volatiles in sweet potato, with potential implications for improving sweet potato weevil management strategies.
危险品化学品经营许可证（带存储）