Identification of a Novel Metabolic Target for Bioactive Triterpenoids Biosynthesis in Ganoderma lucidum

Abstract

Triterpenoids are crucial active ingredients of Ganoderma lucidum (G. lucidum) with various health benefits. Yet the low biosynthesis greatly restricts their industrial applications, novel metabolic engineering strategies are needed to further enhance Ganoderma triterpenoids production. Transcription factors play vital roles in the metabolic regulation of terpenoids, which are still scarce to study in G. lucidum. Herein, a transcription factor GlbHLH5 (GenBank No. MZ436906.1) potential for metabolic regulation of Ganoderma triterpenes was identified for the first time. MeJA could increase Ganoderma triterpenoids biosynthesis, and GlbHLH5 significantly responded to MeJA induction, suggesting GlbHLH5 is a new target for Ganoderma triterpenoids overproduction. The regulatory effect of the newly identified target was further validated by homologous gene overexpression and silence in G. lucidum. It’s demonstrated that overexpression of GlbHLH5 significantly increased triterpenoids accumulation and the key enzyme genes transcription in the biosynthetic pathway, while silencing it displayed the opposite effect, indicating GlbHLH5 could positively regulate the triterpenoids biosynthesis by activating the synergistic expression of key enzyme genes in the biosynthetic pathway. Consequently, GlbHLH5 was identified as a positive regulator and novel metabolic target for Ganoderma triterpenoids biosynthesis, it sheds new lights on the regulatory effect regulation and synthetic biology of Ganoderma triterpenoids.

Methyl Jasmonate- and Salicylic Acid-Induced Transcription Factor ZjWRKY18 Regulates Triterpenoid Accumulation and Salt Stress Tolerance in Jujube

“…In Centella asiatica , MeJA and SA induce expression of triterpene-related genes to increase triterpenoid content [ 4 ]. In addition, silenced and overexpressed Withania somnifera CYP450 and Ganoderma lucidum bHLH reduced and enhanced triterpenoid accumulation, respectively [ 30 , 31 ]. In this study, ZjWRKY18 was significantly upregulated under the action of MeJA and SA, and this up-regulation in response to phytohormones, and the expression of this transcription factor in jujube, may play an important role in triterpenoid biosynthesis.…”

Ganoderma lucidum: Insight into antimicrobial and antioxidant properties with development of secondary metabolites

“…Researchers have concentrated on boosting the production of bioactive substances in G. lucidum , which are responsible for its medicinal properties. These substances include triterpenoids, polysaccharides, and ganoderic acids [ 189 , 190 ]. This is accomplished by either importing genes from other organisms that encode enzymes with desirable activity or by overexpressing important genes involved in the synthesis of these compounds.…”

“…According to reports, overexpression of SQS increases the synthesis of GA-S, GA-Me, GA-T, and GA-MK to varying degrees [ 192 ]. By introducing vitreoscilla hemoglobin (VHb) gene expression in G. lucidum, the synthesis of GAs (GA-S, GA-T, GA-Mk, and GA-Me) was improved relative to the wild types strain [ 190 , 193 ]. Additionally, a recent study indicates that overexpressing the homologous farnesyl diphosphate synthase (FPS) gene in G. lucidium was a successful strategy for increasing secondary metabolite production.…”

Current Advances in the Functional Genes of Edible and Medicinal Fungi: Research Techniques, Functional Analysis, and Prospects

“…Currently, Gl-acat, Gl-hmgs, Gl-hmgr, Gl-mvd, Gl-fps, Gl-sqs, and Gl-ls are the key genes cloned in the triterpene biosynthesis pathway of G. lucidum, and their gene expression levels are consistent with triterpene content [197]. In addition, the biological regulatory factors of Ganoderma triterpenoids include Ca 2+ signaling and plant hormones, such as salicylic acid (SA) and methyl jasmonate (MeJA), which regulate the biosynthesis of Ganoderma triterpenoids and CYP450 inducers [200]. Ganoderic acid is a highly oxidized secondary metabolite of lanosterane-type tetracyclic triterpenoids-classified into type I and type II ganoderic acid-and is an important indicator for controlling the quality of G. lucidum.…”