Screening of housekeeping genes in Gelsemium elegans and expression patterns of genes involved in its alkaloid biosynthesis / 生物工程学报

Gelsemium elegans is a traditional Chinese herb of medicinal importance, with indole terpene alkaloids as its main active components. To study the expression of the most suitable housekeeping reference genes in G. elegans, the root bark, stem segments, leaves and inflorescences of four different parts of G. elegans were used as materials in this study. The expression stability of 10 candidate housekeeping reference genes (18S, GAPDH, Actin, TUA, TUB, SAND, EF-1α, UBC, UBQ, and cdc25) was assessed through real-time fluorescence quantitative PCR, GeNorm, NormFinder, BestKeeper, ΔCT, and RefFinder. The results showed that EF-1α was stably expressed in all four parts of G. elegans and was the most suitable housekeeping gene. Based on the coexpression pattern of genome, full-length transcriptome and metabolome, the key candidate targets of 18 related genes (AS, AnPRT, PRAI, IGPS, TSA, TSB, TDC, GES, G8H, 8-HGO, IS, 7-DLS, 7-DLGT, 7-DLH, LAMT, SLS, STR, and SGD) involved in the Gelsemium alkaloid biosynthesis were obtained. The expression of 18 related enzyme genes were analyzed by qRT-PCR using the housekeeping gene EF-1α as a reference. The results showed that these genes' expression and gelsenicine content trends were correlated and were likely to be involved in the biosynthesis of the Gelsemium alkaloid, gelsenicine.

Strictosidine synthase, an indispensable enzyme involved in the biosynthesis of terpenoid indole and β-carboline alkaloids / 中国天然药物

Terpenoid indole (TIAs) and β-carboline alkaloids (BCAs), such as suppressant reserpine, vasodilatory yohimbine, and antimalarial quinine, are natural compounds derived from strictosidine. These compounds can exert powerful pharmacological effects but be obtained from limited source in nature. the whole biosynthetic pathway of TIAs and BCAs, The Pictet-Spengler reaction catalyzed by strictosidine synthase (STR; EC: 4.3.3.2) is the rate-limiting step. Therefore, it is necessary to investigate their biosynthesis pathways, especially the role of STR, and related findings will support the biosynthetic generation of natural and unnatural compounds. This review summarizes the latest studies concerning the function of STR in TIA and BCA biosynthesis, and illustrates the compounds derived from strictosidine. The substrate specificity of STR based on its structure is also summarized. Proteins that contain six-bladed four-stranded β-propeller folds in many organisms, other than plants, are listed. The presence of these folds may lead to similar functions among organisms. The expression of STR gene can greatly influence the production of many compounds. STR is mainly applied to product various valuable drugs in plant cell suspension culture and biosynthesis in other carriers.

A Research Progress on the Biosynthetic Pathways of Indole Alkaloids / 世界科学技术-中医药现代化

Indole alkaloid family has been the biggest so far among the various alkaloids,which contains pharmaceutical and effective constituents of various plants featuring diverse biological activities.Thanks to the development of metabonomics,to reveal the biosynthetic pathway of active components for the molecular mechanism of indole alkaloids and the regulation research of plant metabolism present a growing importance and significantly direct the researches of improving biological production.This paper reviewed the biosynthetic pathways of some indole alkaloids in accordance with the structure classification of indole alkaloids to lay a foundation for the further studies on the biosynthetic pathways of indole alkaloids and provide a reference for the biosynthetic pathways of other indole alkaloids.

Advance in biosynthesis of terpenoid indole alkaloids and its regulation in Catharanthus roseus / 中国中药杂志

Catharanthus roseus can produce a variety of terpenoid indole alkaloids (TIA), most of which exhibit strong pharmacological activities. Hence, biosynthesis and regulation of TIA have received recent attention. 3α (S)-strictosidine is an important node in TIA biosynthesis, which is a condensation product of secologanin and tryptamine. The former is produced in iridoid pathway, and the latter is produced in indole pathway. Vindoline and catharanthine, which are produced respectively by 3α (S)-strictosidine via multi-step enzymatic reaction, can form α-3, 4-anhydrovinblastine by the condensation reaction. Then, vinblastine and vincristine are generated from α-3, 4-anhydrovinblastine. Many transcription factors are involved in the regulation of TIA synthesis, such as AP2/ERF and WRKY. Illumination of biosynthetic pathway has laid a foundation for the study of synthetic biology. Today, 3α (S)-strictosidine and vindoline have been synthesized in heterologous hosts Saccharomyces cerevisiae.Research about synthetic biology and the regulation mechanisms will provide a guidance for the production and development of TIA drugs in C. roseus.

Codon usage bias of Catharanthus roseus / 中国中药杂志

This study aimed to provide guidance for the heterogenous gene expression, gene prediction and species evolution by analyzing codon usage bias of Catharanthus roseus.The codon composition and usage bias of 30 437 high-confidence coding sequences from C.roseus were analyzed and the proportion of rare codons of Escherichia coli and Saccharomyces cerevisiae in 25 genes involved in the biosynthesis of terpenoid indole alkaloids (TIAs) in C.roseus were calculated.The results showed that the average GC content of the genes was 42.47%; the average GC content of the third bases in codon was 35.89%.The relative synonymous codon usage (RSCU) of 28 codons were greater than 1 and 26 of them ended with A or T.The above 25 genes involved in TIA biosynthesis contained much more rare condons of E.coli than that of S.cerevisiae.It was concluded that C.roseus mainly prefered the codons ending with A or T and the rule of codon usage was more different to E.coli than S.cerevisiae.Thus, S.cerevisiae may be more suitable host for heterologous expression of these genes.