ABSTRACT
Objective To clone the UGD-glucose-dehydrogenase (CsUGD) gene involved in the polysaccharide metabolic pathway, and to analyze by bioinformatics analysis, tissue expression specificity analysis, and determination of polysaccharide content in different organs of Camellia sinensis. Methods The sequence of homologous gene was obtained by transcriptome. The bioinformatics analysis was carried out by using ProtParam, TMpred, signalP, NetPhos, SMART, SSPro 4.0 and so on. Three-dimensional structure of CsUGD protein was edited by VMD; Jalview software was used for multiple sequence alignment; MEGA5.0 was used for phylogenetic tree construction. Gene expression analysis in difference organs was performed by Real-time PCR and the determination of polysaccharide content in different organs was done by anthrone sulfuric acid colorimetric method. Results The cloned CsUGD gene (GenBank accession number MG366591) had a full length of 1 866 bp encoding a predicted protein of 480 amino acids. The results of bioinformatics showed that the protein encoded by CsUGD gene belongs to the stable hydrophilic protein with transmembrane structure but no signal peptide; Phylogenetic tree analysis showed that CsUGD keeps closest genetic relationship with Diospyros kaki. The highest expression was observed in lateral roots by RT-PCR. Determination of polysaccharides in different organs of C. sinensis by colorimetric method of anthrone and sulphuric acid showed that the content of tea polysaccharide (TPS) in lateral root was higher than other parts of C. sinensis. Conclusion The CsUGD gene was cloned from the tea plant for the first time and its important role in the growth and development of the tea tree was clarified. It also played a key role in the pathways of synthesis of C. sinensis polysaccharides, which provided a scientific basis for quality breeding of C. sinensis and improving the medicinal value of tea.