Integrated Metabolomic and Transcriptomic Profiling Reveals the Defense Response of Tea Plants () to .

The tea plant () is a unique beverage crop worldwide, but its yield and quality are adversely affected by . However, the response mechanisms of tea plants to stress remain poorly known. Herein, we present the life table of on resistant (W016) and susceptible (HJY) tea cultivars, demonstrating that the fitness of on W016 was lower than that on HJY. Integrated metabolic and transcriptomic analyses revealed that feeding activated pathways associated with phenylpropanoid biosynthesis, plant hormone signal transduction, and ATP-binding cassette (ABC) transporters. Notably, feeding significantly upregulated the levels of brassinolide and -coumaryl alcohol in W016 but not in HJY. Furthermore, enzymatic assays indicated that cinnamyl alcohol dehydrogenase (CsCAD1) catalyzes the formation of -coumaryl alcohol participation in lignin synthesis. Our findings highlight the role of brassinolide-mediated lignin biosynthesis of the tea plant in response to feeding.