Biotechnology Bulletin ›› 2024, Vol. 40 ›› Issue (1): 281-293.doi: 10.13560/j.cnki.biotech.bull.1985.2023-0641

Previous Articles     Next Articles

Cloning of bHLH96 Gene and Its Roles in Regulating the Biosynthesis of Peppermint Terpenes

WANG Bin1(), YUAN Xiao1,2, JIANG Yuan-yuan1, WANG Yu-kun1, XIAO Yan-hui1, HE Jin-ming1()   

  1. 1. College of Biology and Agriculture, Shaoguan University, Guangdong Provincial Key Laboratory of Utilization and Conservation of Food and Medicinal Resources in Northern Region, Shaoguan 512005
    2. College of Horticulture, South China Agricultural University, Guangzhou 510642
  • Received:2023-07-05 Online:2024-01-26 Published:2024-02-06
  • Contact: HE Jin-ming E-mail:b_wang@sgu.edu.cn;hjm@sgu.edu.cn

Abstract:

【Objective】Peppermint essential oil is an important raw material in the cosmetics, pharmaceutical, and food industries. bHLH transcription factors(TFs)play a crucial role in regulating the biosynthesis of volatile secondary metabolites(VSMs)in plants. Exploring the role of bHLH TFs in the regulation of VSM biosynthesis in peppermint may provide important gene resources for improving peppermint germplasm through metabolic or genetic engineering, and expand our understanding of the pathways and regulatory mechanisms of plant VSM biosynthesis. 【Method】The expression pattern of bHLH96 in peppermint roots, stems, and leaves was analyzed using transcriptome sequencing and qRT-PCR techniques. The full-length of bHLH96 coding sequence(CDS)was cloned using the RT-PCR method. Subsequently, a plant expression vector, pBI121-bHLH96, was constructed using DNA recombination technology, and the overexpression of bHLH96 in the peppermint leaves was achieved through Agrobacterium-mediated transformation. The effects of bHLH96 overexpression on the content of terpenoid compounds and the expression of related genes involved in terpenoid biosynthesis in the peppermint leaves were examined. 【Result】The results showed that the full length of bHLH96 CDS was 861 bp encoding 286 amino acids. Peppermint bHLH96 protein localized at the nucleus, and the sequence similarity among plant bHLH96 proteins ranged from 45.45% to 73.68%. Peppermint bHLH96 had a close relationship with plant bHLH proteins from the Labiatae family such as Lavandula angustifolia LaMYC4 and Salvia miltiorrhiza SmbHLH94. Transient overexpression of the bHLH96 gene in peppermint leaves significantly influenced relative contents of 15 terpenoid compounds. bHLH96 overexpression significantly upregulated the expressions of 5 terpene synthesis-related genes, such as OC2, SM1, KS1, ND, and EAO1, while downregulated the expressions of NLS1, LS1 and iPR. 【Conclusion】Peppermint bHLH96 might regulate terpene synthesis by modulating the expressions of terpene synthesis-related genes and influencing the activities of terpene synthases.

Key words: peppermint, essential oil, volatile compound, synthetic regulation, bHLH transcription factor