Tandem expression of Ganoderma sinense sesquiterpene synthase and IDI promotes the production of gleenol in E. coli.

Ganoderma sinense, with more than 2000 years of medicinal history, is a fungus of the basidiomycetes that is rich in polysaccharides and terpenoids. However, the biosynthesis of terpenes, especially sesquiterpenes, has been little studied. The functional identification of sesquiterpene synthases from G. sinense is of great significance to the study of fungal terpenoid biosynthesis and regulation. Our research group has completed the functional characterization of 21 sesquiterpene synthase genes from G. sinense. It was found that gleenol, biosynthesis of which is catalyzed by the sesquiterpene synthase GsSTS26 and GsSTS27, has the functions of killing termites, antihelminth, and plant growth regulation. In the unmodified E. coli Rosetta (DE3) strain, the content of gleenol produced by sesquiterpene synthase from G. sinense is low, which makes it difficult to meet the demand of industrial production and the market. Therefore, it is of great significance to obtain high-yielding strains by means of synthetic biology. In this study, we constructed eight recombinant strains by using tandem gene expression and promoter engineering, and the content of gleenol was increased by up to 23-fold. In this study, we realized the de novo synthesis of gleenol in E. coli and provided a basis for the biosynthesis of terpenoids in basidiomycetes. KEY POINTS: • Eight recombinant expression systems were constructed by using tandem genes and promoter engineering. • The recombinant strain promoted the efficient production of gleenol in E. coli Rosetta (DE3). • The recombinant strain achieved de novo production of gleenol in E. coli.

Characterization of γ-Cadinene Enzymes in Ganoderma lucidum and Ganoderma sinensis from Basidiomycetes Provides Insight into the Identification of Terpenoid Synthases.

Enzymes boost protein engineering, directed evolution, and the biochemical industry and are also the cornerstone of metabolic engineering. Basidiomycetes are known to produce a large variety of terpenoids with unique structures. However, basidiomycetous terpene synthases remain largely untapped. Therefore, we provide a modeling method to obtain specific terpene synthases. Aided by bioinformatics analysis, three γ-cadinene enzymes from Ganoderma lucidum and Ganoderma sinensis were accurately predicted and identified experimentally. Based on the highly conserved amino motifs of the characterized γ-cadinene enzymes, the enzyme was reassembled as model 1. Using this model as a template, 67 homologous sequences of the γ-cadinene enzyme were screened from the National Center for Biotechnology Information (NCBI). According to the 67 sequences, the same gene structure, and similar conserved motifs to model 1, the γ-cadinene enzyme model was further improved by the same construction method and renamed as model 2. The results of bioinformatics analysis show that the conservative regions of models 1 and 2 are highly similar. In addition, five of these sequences were verified, 100% of which were γ-cadinene enzymes. The accuracy of the prediction ability of the γ-cadinene enzyme model was proven. In the same way, we also reanalyzed the identified Δ6-protoilludene enzymes in fungi and (-)-α-bisabolol enzymes in plants, all of which have their own unique conserved motifs. Our research method is expected to be used to study other terpenoid synthases with a similar or the same function in basidiomycetes, ascomycetes, bacteria, and plants and to provide rich enzyme resources.

Biosynthesis and regulation of terpenoids from basidiomycetes: exploration of new research.

Basidiomycetes, also known as club fungi, consist of a specific group of fungi. Basidiomycetes produce a large number of secondary metabolites, of which sesquiterpenoids, diterpenoids and triterpenoids are the primary components. However, these terpenoids tend to be present in low amounts, which makes it difficult to meet application requirements. Terpenoid biosynthesis improves the quantity of these secondary metabolites. However, current understanding of the biosynthetic mechanism of terpenoids in basidiomycetes is insufficient. Therefore, this article reviews the latest research on the biosynthesis of terpenoids in basidiomycetes and summarizes the CYP450 involved in the biosynthesis of terpenoids in basidiomycetes. We also propose opportunities and challenges for chassis microbial heterologous production of terpenoids in basidiomycetes and provide a reference basis for the better development of basidiomycete engineering.