Identification and expression of uridine diphosphate glycosyltransferase(UGT) gene family from Dendrobium officinale / 中国中药杂志

Uridine diphosphate glycosyltransferase(UGT) is a highly conserved protein in plants, which usually functions in secondary metabolic pathways. This study used the Hidden Markov Model(HMM) to screen out members of UGT gene family in the whole genome of Dendrobium officinale, and 44 UGT genes were identified. Bioinformatics was used to analyze the structure, phylogeny, and promoter region components of D. officinale genes. The results showed that UGT gene family could be divided into four subfamilies, and UGT gene structure was relatively conserved in each subfamily, with nine conserved domains. The upstream promoter region of UGT gene contained a variety of cis-acting elements related to plant hormones and environmental factors, indicating that UGT gene expression may be induced by plant hormones and external environmental factors. UGT gene expression in different tissues of D. officinale was compared, and UGT gene expression was found in all parts of D. officinale. It was speculated that UGT gene played an important role in many tissues of D. officinale. Through transcriptome analysis of D. officinale mycorrhizal symbiosis environment, low temperature stress, and phosphorus deficiency stress, this study found that only one gene was up-regulated in all three conditions. The results of this study can help understand the functions of UGT gene family in Orchidaceae plants and provide a basis for further study on the molecular regulation mechanism of polysaccharide metabolism pathway in D. officinale.

Correlation analysis and breeding application of agronomic traits and quality indexes in Dendrobium nobile / 中国中药杂志

The present study aimed to explore the correlation between agronomic traits and quality indexes of Dendrobium nobile and its application value in agricultural breeding. The cultivated strains of D. nobile in Hejiang-Chishui producing areas were extensively collected,and the main agronomic traits and quality indexes were measured. The agronomic traits with significant correlation with quality indexes were screened out by the correlation analysis,and then the parental lines and self-bred F_1 generation plants were furtherverified. Among 96 lines of D. nobile,the content of soluble polysaccharides showed a significant negative correlation with dendrobine( P < 0. 01),and no significant correlation with agronomic traits in stems and leaves. The content of dendrobine exhibited a significant positive correlation with the stem width-thickness ratio( at the largest cross section; P < 0. 01),and no significant correlation with other agronomic traits. Regression analysis further verified the positive correlation between dendrobine content and stem width-thickness ratio( R2> 0. 9). Two lines,JC-10 and JC-35,with significant differences in stem width-thickness ratio were screened out( P <0. 05). The corresponding F1 generation plants by self-pollination both showed that the dendrobine content was higher with greater stem width-thickness ratio( P < 0. 01). The experimental results suggested that within a certain range,the dendrobine content was higher in D. nobile with flatter stem. Therefore,in the breeding of D. nobile,this specific trait could be used for screening plants with high content of quality indexes such as dendrobine.

Comparative analysis of active components and transcriptome between autotetraploid and diploid of Dendrobium huoshanense / 中国中药杂志

In this study, the roots, stems and leaves of diploid and autotetraploid Dendrobium huoshanense were used as materials to compare their contents of polysaccharides and alkaloids, and the transcriptome sequencing analysis was carried out. The results showed that the contents of polysaccharides and alkaloids in the roots, stems and leaves of tetraploid were 7.6%, 34.5%, 17.2%, 0.01%, 0.024% and 0.035% higher than those of diploid D. huoshanense, respectively. The contents of active components in different tissues were significantly different. There were 3 687 differentially expressed genes in diploid and tetraploid D. huoshanense, of which 2 346 genes were up-regulated and 1 341 down regulated. Go functional analysis showed that these genes were mainly involved in growth and development, stress resistance and other related functions. KEGG pathway analysis showed that most of the differential genes were concentrated in the processes of carbon metabolism, signal transduction, carbohydrate metabolism, amino acid metabolism and energy metabolism. The differential expression of key genes involved in the metabolism of polysaccharides, terpenes and polyketones, amino acid metabolism, hormone synthesis and signal transduction in diploid and tetraploid plants may be the main reason for the high energy content, the increase of active components and the growth potential of tetraploid plants.