Molecular genetics of medicinal plants, past achievement, and new era / 中国中药杂志

Unraveling the genetic basis of medicinal plant metabolism and developmental traits is a long-standing goal for pharmacologists and plant biologists. This paper discusses the definition of molecular genetics of medicinal plants, which is an integrative discipline with medicinal plants as the research object. This discipline focuses on the heredity and variation of medicinal plants, and elucidates the relationship between the key traits of medicinal plants(active compounds, yield, resistance, etc.) and genotype, studies the structure and function, heredity and variation of medicinal plant genes mainly at molecular level, so as to reveal the molecular mechanisms of transmission, expression and regulation of genetic information of medicinal plants. Specifically, we emphasize on three major aspects of this discipline.(1)Individual and population genetics of medicinal plants, this part mainly highlights the genetic mechanism of the domestication, the individual genomics at the species level, and the formation of genetic diversity of medicinal plants.(2)Elucidation of biosynthetic pathways of active compounds and their evolutionary significance. This part summarizes the biosynthesis, diversity and molecular evolution of active compounds in medicinal plants.(3) Molecular mechanisms that shaping the key agronomic traits by internal and external factors. This part focuses on the accumulation and distribution of active compounds within plants and the regulation of metabolic network by environmental factors. Finally, we prospect the future direction of molecular genetics of medicinal plants based on the rapid development of multi-omics technology, as well as the application of molecular genetics in the future strategies to achieve conservation and breeding of medicinal plants and efficient biosynthesis of active compounds.

Synthesis of triterpenoid saponins from Aesculus chinensis based on transcriptome data / 中国中药杂志

Aesculus chinensis belongs to Hippocastanaceae family,bears medicinal and ornamental values. The oleanane type triterpenoid saponin aescin is regarded as active ingredient and accumulated in seed. In order to understand its molecular basis of the triterpenoid biosynthesis,we used high-throughput sequencing under Illumina Hi Seq 2000 platform to obtain the transcriptome data of seed and flower from A. chinensis to further mine the genes involved in its metabolic pathway. Unigene's de novo splicing was performed using Trinity software; the transcriptome results were annotated with KEGG database to predict the specific pathways of the aescin triterpenoid metabolism. Terpenoid and triterpenoid pathways were found from transcriptome data,and forty seven and twenty seven corresponding genes were uncovered respectively. It was found that there are eight kinds of enzymes related to the terpenoid metabolism pathway precursors and three kinds of enzymes related to the triterpenoid metabolism pathway. In this study,five genes corresponding to triterpene cyclase were analyzed in A. chinensis for the first time,which may participate in the synthesis of triterpenoid. It' s revealed that there were thirty three differential genes associated with the ko00900 and ko00909 pathways by analysis on the difference in transcriptome expression between seeds and flowers; seventeen unigenes were up-regulated and sixteen unigenes were down-regulated in the seeds relative to flowers. In this study, qRT-PCR experiments were used to verify the expression of three key enzyme genes of SQE( Unigene25806),HMGS( Unigene36710),and β-AS( Unigene33291). The results of qRT-PCR were consistent with the transcriptome data. The candidate genes related to triterpenoid saponin aescin synthesis in A. chinensis found in this study can provide theoretical basis for the metabolism synthesis and regulation of aescin.