Identification and functional analysis of associated with the response to biotic stress in maize.

Terpenes are the main class of secondary metabolites produced in response to pest and germ attacks. In maize ( L.), they are the essential components of the herbivore-induced plant volatile mixture, which functioned as a direct or indirect defense against pest and germ attacks. In this study, 43 maize terpene synthase gene () family members were systematically identified and analyzed through the whole genomes of maize. Nine genes, including , , , , , , , , and , were isolated for their differential expression pattern in leaves after corn borer () bite. Additionally, six genes (, , , , , and ) were significantly upregulated in response to corn borer bite. Among them, was cloned. Heterologous expression and enzyme activity assays revealed that functioned as d-limonene synthase. It was renamed . Further analysis demonstrated that its expression was upregulated in response to corn borer bites and attacks. The mutant of downregulated the expressions of , , , , and . It was more attractive to corn borer bites and more susceptible to infection. The yeast one-hybrid assay and dual-luciferase assay showed that ZmMYB76 and ZmMYB101 could upregulate the expression of by binding to the promoter region. This study may provide a theoretical basis for the functional analysis and transcriptional regulation of terpene synthase genes in crops.