[Bioinformation analysis of chorismate synthase in Baphicacantus cusia and other 78 species of plants].

Chorismate synthase(CS, EC:4.2.3.5) catalyses 5-enolpyruvy-shikimate-3-phosphate to form chorismate, which is the essential enzyme for chorismate biosynthesis in organisms. The amino acid sequences of CS from 79 species of higher plants were reported in GenBank at present. 125 amino acid sequences of CS from Baphicacanthus cusia and other 78 species of plants were predicted and analyzed by using various bioinformatics software, including the composition of amino acid sequences, signal peptide, leader peptide, hydrophobic/hydrophilic, transmembrane structure, coiled-coil domain, protein secondary structure, tertiary structure and functional domains. The phylogenetic tree of CS protein family was constructed and divided into eight groups by phylogenetic analysis. The homology comparison indicated that B. cusia shared a high homology with several plants such as Sesamum indicum, Nicotiana tabacum, Solanum tuberosum and so on. The open reading frame(ORF) of all samples is about 1 300 bp, the molecular weight is about 50 kDa, the isoelectric point(pI) is 5.0-8.0 which illustrated that CS protein is slightly basic. The ORF of CS we cloned in B. cusia is 1 326 bp, the amino acid residues are 442, the molecular weight is 47 kDa and pI is 8.11. The CS in B.cusia showed obvious hydrophobicity area and hydrophilicity area, no signal peptide, and may exists transmembrane structure areas. The main secondary structures of CS protein are random coil and Alpha helix, also contain three main structural domains which are an active structural domain, a PLN02754 conserved domain and a FMN binding site. The acquired information in this study would provide certain scientific basis for further study on structure-activity relationship and structure modification of CS in plants in the future.

[Molecular mechanism of artemisinin biosynthesis and regulation in Artemisia annua].

Artemisinin-based combination therapy (ACT) is the best available treatment, particularly for Plasmodium falciparum malaria. Artemisinin, whose main source is Artemisia annua, has large demand and shortsupply every year.Artemisininis synthesized,stored, and secreted by the glandular secretory trichomes of A. annua(AaGSTs).In general, the population and morphology of AaGSTs are often positively correlated with artemisinin content.This review article introduces the molecular mechanism of biosynthesis and regulation of artemisininin A. annua. Furthermore, this article will refresh the classification of trichomes in A. annua and provide anoverview of the recent achievements regarding AaGSTs and artemisinin.These will shed light on exploring the method for increasing plant-derived artemisinin.

HPPR encodes the hydroxyphenylpyruvate reductase required for the biosynthesis of hydrophilic phenolic acids in Salvia miltiorrhiza.

Salvia miltiorrhiza is a medicinal plant widely used in the treatment of cardiovascular and cerebrovascular diseases. Hydrophilic phenolic acids, including rosmarinic acid (RA) and lithospermic acid B (LAB), are its primary medicinal ingredients. However, the biosynthetic pathway of RA and LAB in S. miltiorrhiza is still poorly understood. In the present study, we accomplished the isolation and characterization of a novel S. miltiorrhiza Hydroxyphenylpyruvate reductase (HPPR) gene, SmHPPR, which plays an important role in the biosynthesis of RA. SmHPPR contained a putative catalytic domain and a NAD(P)H-binding motif. The recombinant SmHPPR enzyme exhibited high HPPR activity, converting 4-hydroxyphenylpyruvic acid (pHPP) to 4-hydroxyphenyllactic acid (pHPL), and exhibited the highest affinity for substrate 4-hydroxyphenylpyruvate. SmHPPR expression could be induced by various treatments, including SA, GA3, MeJA and Ag+, and the changes in SmHPPR activity were correlated well with hydrophilic phenolic acid accumulation. SmHPPR was localized in cytoplasm, most likely close to the cytosolic NADPH-dependent hydroxypyruvate reductase active in photorespiration. In addition, the transgenic S. miltiorrhiza hairy roots overexpressing SmHPPR exhibited up to 10-fold increases in the products of hydrophilic phenolic acid pathway. In conclusion, our findings provide a new insight into the synthesis of active pharmaceutical compounds at molecular level.

Deep Sequencing Reveals the Effect of MeJA on Scutellarin Biosynthesis in Erigeron breviscapus.

BACKGROUND: Erigeron breviscapus, a well-known traditional Chinese medicinal herb, is broadly used in the treatment of cerebrovascular disease. Scutellarin, a kind of flavonoids, is considered as the material base of the pharmaceutical activities in E. breviscapus. The stable and high content of scutellarin is critical for the quality and efficiency of E. breviscapus in the clinical use. Therefore, understanding the molecular mechanism of scutellarin biosynthesis is crucial for metabolic engineering to increase the content of the active compound. However, there is virtually no study available yet concerning the genetic research of scutellarin biosynthesis in E. breviscapus. RESULTS: Using Illumina sequencing technology, we obtained over three billion bases of high-quality sequence data and conducted de novo assembly and annotation without prior genome information. A total of 182,527 unigenes (mean length = 738 bp) were found. 63,059 unigenes were functionally annotated with a cut-off E-value of 10(-5). Next, a total of 238 (200 up-regulated and 38 down-regulated genes) and 513 (375 up-regulated and 138 down-regulated genes) differentially expressed genes were identified at different time points after methyl jasmonate (MeJA) treatment, which fell into categories of 'metabolic process' and 'cellular process' using GO database, suggesting that MeJA-induced activities of signal pathway in plant mainly led to re-programming of metabolism and cell activity. In addition, 13 predicted genes that might participate in the metabolism of flavonoids were found by two co-expression analyses in E. breviscapus. CONCLUSIONS: Our study is the first to provide a transcriptome sequence resource for E. breviscapus plants after MeJA treatment and it reveals transcriptome re-programming upon elicitation. As the result, several putative unknown genes involved in the metabolism of flavonoids were predicted. These data provide a valuable resource for the genetic and genomic studies of special flavonoids metabolism and further metabolic engineering in E. breviscapus.