Integrated metabolomic and transcriptomic profiling reveals the defense response of tea plants (Camellia sinensis) to Basilepta melanopus

Summary: Tea (Camellia sinensis) is one of the world’s most consumed beverages, its yield and quality are often compromised by infestations of the leaf beetle Basilepta melanopus. To elucidate the defense mechanisms of tea plants, we constructed time-resolved models of tea responses to B. melanopus herbivory. Integrated metabolomic and transcriptomic analyses revealed that infestation significantly increased abundance of aromatic and amide amino acids, elevated the levels of jasmonic acid (JA), auxins, and indole-related compounds, while reducing salicylic acid content. Notable alterations were also observed in metabolites such as polyphenols, catechins, organic acids, and soluble sugars. Furthermore, WGCNA analysis revealed that CsLOX2.1, CsLOX2.2, CsLOX2.3 and CsLOX3, as well as transcription factor CsMYC2, may be core genes involved in JA biosynthesis, potentially regulated by transcription factor CsWRKY23. Suppression of CsWRKY23 expression by AsODN in tea leaves led to a downregulation of CsMYC2, CsLOX2.1, CsLOX2.2, and CsLOX3. Collectively, our findings demonstrate that the CsMYC2-CsWRKY23-CsLOXs regulatory cascade orchestrates JA-dependent defense in tea leaves against B. melanopus, providing a molecular foundation for breeding insect-resistant tea cultivars.