Transcription Factors ZjMYB39 and ZjMYB4 Regulate Farnesyl Diphosphate Synthase- and Squalene Synthase-Mediated Triterpenoid Biosynthesis in Jujube

Abstract

Jujube (Ziziphus jujuba Mill.) is rich in valuable bioactive triterpenoids. However, the regulatory mechanism underlying triterpenoid biosynthesis in jujube remains poorly studied. Here, we characterized the triterpenoid content in wild jujube and cultivated jujube. The triterpenoid content was higher in wild jujube than in cultivated jujube, triterpenoids were most abundant in young leaves, buds, and later stages of development. The transcriptome analysis and correlation analysis showed that differentially expressed genes (DEGs) were enriched in the terpenoid synthesis pathways, and triterpenoids content was strongly correlated with farnesyl diphosphate synthase (ZjFPS), squalene synthase (ZjSQS), and transcription factors ZjMYB39 and ZjMYB4 expression. Gene overexpression and silencing analysis indicated that ZjFPS and ZjSQS were key genes in triterpenoid biosynthesis and transcription factors ZjMYB39 and ZjMYB4 regulated triterpenoid biosynthesis. Subcellular localization experiments showed that ZjFPS and ZjSQS were localized to the nucleus and endoplasmic reticulum and ZjMYB39 and ZjMYB4 were localized to the nucleus. Yeast one-hybrid, glucuronidase activity, and dual-luciferase activity assays suggested that ZjMYB39 and ZjMYB4 regulate triterpenoid biosynthesis by directly binding and activating the promoters of ZjFPS and ZjSQS. These findings provide insights into the underlying regulatory network of triterpenoids metabolism in jujube and lay theoretical and practical foundation for molecular breeding.

Terpenoid balance in Aspergillus nidulans unveiled by heterologous squalene synthase expression

“…Although the role of squalene as an ergosterol precursor is well known ( 22 ), recent papers have shown that alternative functions of SqsA and SqsA-like enzymes and subsequent squalene synthesis are involved in induction of terpenoids in plants ( 23 , 24 ) and bacteria ( 25 ). We thus hypothesized that A. nidulans transformants expressing PdFAC1 could be altered in terpenoid production.…”

Comparative physiological, biochemical, metabolomic, and transcriptomic analyses reveal the formation mechanism of heartwood for Acacia melanoxylon

“…Geranylgeranyl diphosphate (GGPP) produced by GGDS serves as a precursor for many diphosphates, including farnesyl-PP, Geranylgeranyl-PP, and Geranyl-PP [ 52 , 53 ]. Farnesyl-diphosphate (FPS) reduced farnesyl-PP to squalene, and then squalene monooxygenase (SME) oxidized squalene to (s)-squalene-2, 3-epoxide in sesquiterpenoid and triterpenoid biosynthesis [ 54 , 55 ]. Up-regulation of FPS and SME transcripts may indicate a relatively high accumulation of F-PP and squalene for sesquiterpenes and monoterpenes in HW.…”

The Transcriptional Regulatory Mechanisms Exploration of Jujube Biological Traits through Multi-Omics Analysis

“…Wen (2023) [63] further explored the role of ZjWRKY18 (evm.model.Contig24.0.57) in activating ZjHMGR (evm.model.Contig21.0.64 and evm.model.Contig112.45) and ZjFPS, promoting triterpene accumulation. Wen et al (2023) [64] analyzed enzymes related to terpenoid synthesis through transcriptome analysis and identified ZjFPS, ZjSQS, and the corresponding transcription factors, ZjMYB39 (evm.model.Contig108.375) and ZjMYB4 (evm.model.Contig23.4.315), as key genes for the biosynthesis of jujube triterpenoids. However, the corresponding transcription factor of ZjSQE is still unclear (Figure 2).…”