Repeated mechanical damage enhanced Aquilaria sinensis resistance to Heortia vitessoides through jasmonic acid

IntroductionThe leaf-chewing pest Heortia vitessoides severely threatens the growth and development of Aquilaria sinensis. In our previous study, we found that mechanical damage (MD) to stem enhanced A. sinensis sapling resistance to H. vitessoides larvae. MethodsTo reveal the defense mechanisms underlying this observation, we analyzed the types and contents of volatile organic compounds (VOCs), phytohormone contents, and expression of phytohormone-related genes in response to MD and herbivory wounding(HW). ResultsHere, we identified several VOCs, such as the pesticides fenobucarb and 2,4-di-tert-butylphenol, in mature leaf (ML) of MD-treated plants. Compared with salicylic acid (SA) or the ethylene (ET) pathway, jasmonic acid (JA) content and JA-related genes were more strongly upregulated. Interestingly, we found a dramatic difference between JA-related upstream and downstream genes expression in YL and ML, which confirmed that JA-Ile accumulation in MD-ML and HW-ML could be derived from local damaged site. DiscussionTaken together, we provide evidence that the JA pathway plays a dominant role in the A. sinensis response to MD and HW.

Automated summary

In this study, we investigated the defense mechanisms of Aquilaria sinensis saplings in response to mechanical damage and herbivory wounding. We identified specific volatile organic compounds and observed upregulation of jasmonic acid-related genes, indicating the dominance of the JA pathway in the plant's response.