Gene Cloning and Bioinformatics Analysis of Limonene-3-hydroxylase from Schizonepeta tenuifolia / 中国实验方剂学杂志

Objective:This paper aims to clone the cDNA sequence of<italic> limonene</italic>-3-<italic>hydroxylase</italic>（<italic>StL</italic>3<italic>OH</italic>） in <italic>Schizonepeta tenuifolia</italic> and analyze its sequence by bioinformatics. Method:Specific primers were designed based on sequences of<italic> StL</italic>3<italic>OH </italic>gene screened from transcriptome sequencing data of <italic>S. tenuifolia</italic> and the cDNA sequence of <italic>StL</italic>3<italic>OH </italic>gene was cloned by reverse transcription polymerase chain reaction （RT-PCR） and analyzed for its bioinformatics. Result:The <italic>StL3OH</italic> gene cDNA sequence length was 1 598 bp，containing a 1 497 bp long complete open reading frame which encoded 498 amino acids. StL3OH protein had a theoretical relative molecular mass of 56.40 kDa，with a hydrophilic and unstable nature. Bioinformatics analysis showed that StL3OH protein had no signal peptide but had a transmembrane domain which might be located in endoplasmic reticulum. Multiple sequence alignment and cluster analysis showed that the amino acid sequence of MsL3OH protein had a high similarity with StL3OH protein，both of which contained cytochrome P450 heme binding region，belonging to the D subfamily of cytochrome CYP71 family. Codon bias analysis showed that <italic>StL</italic>3<italic>OH</italic> gene preferred guanine/cytosine（G/C） ending codon，with 27 skewed codons， and Nicotiana benthamiana was proven to be the most suitable host for exogenous expression of <italic>StL</italic>3<italic>OH</italic> gene. Conclusion:The cDNA sequence of<italic> StL3OH</italic> gene was cloned from <italic>S. tenuifolia</italic> for the first time，which will provide a basis for further study on the structure and function of StL3OH protein and the regulation mechanism of <italic>StL3OH </italic>gene in the accumulation and biosynthesis of monoterpenes in<italic> S. tenuifolia</italic>.

Expression profiling and functional verification of flavonoid 3'-hydroxylase gene from leaves of Euryale ferox / 中国中药杂志

Leaves of Euryale ferox are rich in anthocyanins. Anthocyanin synthesis is one of the important branches of the flavonoid synthesis pathway, in which flavonoid 3'-hydroxylase(F3'H) can participate in the formation of important intermediate products of anthocyanin synthesis. According to the data of E. ferox transcriptome, F3'H cDNA sequence was cloned in the leaves of E. ferox and named as EfF3'H. The correlation between EfF3'H gene expression and synthesis of flavonoids was analyzed by a series of bioinforma-tics tools and qRT-PCR. Moreover, the biological function of EfF3'H was verified by the heterologous expression in yeast. Our results showed that EfF3'H comprised a 1 566 bp open reading frame which encoded a hydrophilic transmembrane protein composed of 521 amino acid residues. It was predicted to be located in the plasma membrane. Combined with predictive analysis of conserved domains, this protein belongs to the cytochrome P450(CYP450) superfamily. The qRT-PCR results revealed that the expression level of EfF3'H was significantly different among different cultivars and was highly correlated with the content of related flavonoids in the leaves. Eukaryotic expression studies showed that EfF3'H protein had the biological activity of converting kaempferol to quercetin. In this study, EfF3'H cDNA was cloned from the leaves of E. ferox for the first time, and the biological function of the protein was verified. It provi-ded a scientific basis for further utilizing the leaves of E. ferox and laid a foundation for the further analysis of the biosynthesis pathway of flavonoids in medicinal plants.

Cloning and Sequence Analysis of Cellulose Synthase-like Gene from Ampelopsis megalophylla / 中国实验方剂学杂志

Objective:To clone cellulose synthase-like(Csl)gene from ethnic medicinal plant Ampelopsis megalophylla,and analyze its sequence by bioinformatics. Method:Specific primers were designed for AmCsl gene sequences obtained from A. megalophylla transcriptome sequencing data. The full-length cDNA of AmCsl gene was amplified by PCR using cDNA of young leaves as template,and TA clone and sequencing was performed. The sequence was analyzed by bioinformatics. Result:The full length cDNA was 1 438 bp,containing a 561 bp open reading frame(ORF),and encoding 186 amino acids,the molecular formula of protein was C1011H1547N233O257S10,the theoretical relative molecular weight was 22.40 kDa,the theory isoelectric point(PI)was 7.59,and the aliphatic index(AI)was 116.88.There was a transmembrane region and no signal peptide,which may be located in the endoplasmic reticulum,the average hydrophobic coefficient was 0.670,and the instability index was 42.56.It belonged to a hydrophobic unstable protein. The conserved domain contained a cellulose synthase,and the secondary structure mainly was dominated by α-helix. Amino acid sequence alignment and phylogenetic tree analysis showed that AmCsl had a high homology with Vitis vinifera. Conclusion:The full length of AmCsl gene was obtained for preliminary bioinformatics analysis,which laid a necessary foundation for further study on the accumulation of polysaccharides and the regulation of biosynthesis.

Cloning and bioinformatics analysis of β-1,4-xylosyltransferase IRX9 gene from Dendrobium huoshanense / 中草药

Objective To clone IRX9 gene from Dendrobium huoshanense and perform the bioinformatics and codon bias analysis. Methods The full-length cDNA sequence was cloned from the IRX9 gene based on transcriptome sequencing data of D. huoshanense generated in our previous study by using RT-PCR and further analyzed by bioinformatic methods. Results The cloned IRX9 gene was 1 533 bp, containing a 1 047 bp open reading frame (ORF) which encoded 348 amino acids. The theoretical molecular weight was 39 350 and its isoelectric point was 7.26. IRX9 protein was a hydrophilic protein and had no signal peptide, which had multiple phosphorylation sites and glycosylation sites and might be located in the plasma membrane. Phylogenetic analysis indicated that sequence of amino acids had the highest homology with D. candidum and the conserved region “DXD” of the GT-A superfamily. Codon bias analysis showed that IRX9 gene prefered to use A/T ending codon, with 27 skewed codons. Nicotiana is the most suitable host for exogenous expression of IRX9 gene. Conclusion The IRX9 gene was cloned from Dendrobium huoshanense successfully and it provided a theoretical basis for regulating the growth and development of D. huoshanense and improving the yield and quality of D. huoshanense.