Perilla frutescens (L.) Britt. is a traditional medicinal and culinary plant with a long history of cultivation and significant potential for broader utilization. The basic helix-loop-helix (bHLH) gene family is essential for regulating plant growth, development, stress responses, and secondary metabolism. However, the bHLH gene family in P. frutescens has not yet been characterized. In this study, a total of 205 bHLH genes were identified in P. frutescens through genome mining and analysis. Phylogenetic analysis classified these PfbHLH genes into 23 distinct subfamilies. Promoter analysis revealed an enrichment of cis-acting elements linked to plant hormone signaling and stress responses, suggesting their potential regulatory roles in development, growth, and stress adaptation. Expression profiling based on publicly available RNA-seq data demonstrated tissue-specific expression patterns of PfbHLH genes in roots, stems, and leaves. Four PfbHLH genes (PfbHLH66, PfbHLH45, PfbHLH13, and PfbHLH5) showed significant responses to methyl jasmonate (MeJA) induction. Yeast one-hybrid assays confirmed that these PfbHLH proteins could bind to the cis-acting G-box (CACGTG) element. This study offers new perspectives on the evolution, regulatory mechanisms, and functional roles of the bHLH gene family in P. frutescens. The findings deepen our understanding of the functional diversity within this gene family and establish a foundation for genetic enhancement and the biosynthesis of medicinal compounds in the species.
Keywords: MeJA; Perilla frutescens; Y1H; bHLH family.