Effects of Compound Elicitors on the Biosynthesis of Triterpenoids and Activity of Defense Enzymes from Inonotus hispidus (Basidiomycetes)

Regulation of gene expression in the secondary metabolic synthesis pathway of Lonicera japonica Flos by yeast polysaccharides

Lonicera japonica Flos is a valuable herb in the Lonicerae family. While transcriptomic studies on L. japonica have focused on different tissues (stems, leaves, flowers) or flowering stages, few have investigated the molecular mechanisms underlying chemical composition synthesis influenced by exogenous factors, such as foliar fertilization. Moreover, most transcriptomic studies on L. Japonica have been conducted on chlorogenic acid and luteoloside, and the molecular synthesis mechanism of the overall chemical composition has not been analyzed. Methods: We conducted a single-factor, four-level foliar fertilization experiment using yeast polysaccharides. Different yeast polysaccharides concentrations were sprayed on L. japonica for six consecutive days with dynamic sampling. High-performance liquid chromatography determined the active ingredients in each group. The two groups exhibiting the most significant differences were selected for transcriptomic analysis to identify key synthetic genes responsible for L. japonica's active ingredients. Key results: Principal component analysis conducted on samples collected on September 8 revealed significant differences in the active ingredient amounts between the 0.1 g/L yeast polysaccharides treatment group and the control group. Transcriptome sequencing analysis identified 218 significantly differentially expressed genes, including 60 upregulated and 158 downregulated genes. Twelve differential genes involved in the chemical components synthesis pathway of L. japonica under yeast polysaccharides treatment were identified: PAL1, PAL2, PAL3, 4CL1, 4CL, CHS1, CHS2, CHS, CHI1, CHI2, F3H, and SOH. Conclusions: This study contributes to the theoretical understanding of essential synthetic genes associated with L. japonica's active ingredients. It offers data support for further gene exploration and sheds light on the molecular mechanisms underlying L. japonica quality formation. These findings hold significant implications for enhancing the content of secondary metabolites of L. japonica.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12298-024-01482-1.

Transcriptional Responses for Biosynthesis of Triterpenoids in Exogenous Inducers Treated Inonotus Hispidus Using RNA-Seq

Inonotus hispidus is a traditional medicinal that grows in Northeast China and produces various economically important compounds, including polysaccharide compounds and terpenoids; triterpenoid saponins is the main bioactive component. Our research group has found that the accumulation of triterpenoid was affected by exogenous inducers. Experimental results showed that treatment with methyl jasmonate (MeJA) and oleic acid significantly increased the triterpenoid content of I. hispidus. However, how exogenous inducers enhance production of secondary metabolites in I. hispidus is not well understood. In this study, metabolite changes were further investigated with UPLC-TOF/MS following exogenous inducer treatment. As a result, a total of eight types of triterpenoids in I. hispidus were identified. The RNA-seq analysis was used to evaluate the effects of exogenous inducers on the expression of triterpenoid-synthesis-related genes in I. hispidus in liquid fermentation. This study is the first exploration to profile the transcriptome of I. hispidus after adding exogenous inducers; the generated data and gene will facilitate further molecular studies on the physiology and metabolism in this fungi. By comparative transcriptomic analysis, a series of candidate genes involved in the biosynthetic pathway of triterpenoids are identified, providing new insights into their biosynthesis at the transcriptome level.

Diverse Metabolites and Pharmacological Effects from the Basidiomycetes Inonotus hispidus

Inonotus hispidus mushroom is a popular edible and medicinal mushroom with a long history of use. It is well known as a medicinal fungus with various health benefits for its significant anticancer and immunomodulatory activities. Over the last 60 years, secondary metabolites derived from I. hispidus and their biological activities have been discovered and investigated. Structurally, these compounds are mainly polyphenols and triterpenoids, which have anticancer, anti-inflammatory, antioxidant, antimicrobial, and enzyme inhibitor activities. Here, the secondary metabolites derived from I. hispidus and their activities were systematically and comprehensively classified and summarized, and the biosynthetic pathway of stylylpyrones was deduced and analyzed further. This review contributes to our understanding of I. hispidus and will help with research into natural product chemistry, pharmacology, and the biosynthesis of I. hispidus metabolites. According to this review, I. hispidus could be a promising source of bioactive compounds for health promotion and the development of functional foods.