Identification and expression profiling of selected MADS-box family genes in Dendrobium officinale.

Dendrobium officinale, a herb with highly medicinal and ornamental value, is widely distributed in China. MADS-box genes encode transcription factors that regulate various growth and developmental processes in plants, particular in flowering. However, the MADS-box genes in D. officinale are largely unknown. In our study, expression profiling analyses of selected MADS-box genes in D. officinale were performed. In total, 16 DnMADS-box genes with full-length ORF were identified and named according to their phylogenetic relationships with model plants. The transient expression of eight selected MADS-box genes in the epidermal cells of tobacco leaves showed that these DnMADS-box proteins localized to the nucleus. Tissue-specific expression analysis pointed out eight flower-specific expressed MADS-box genes in D. officinale. Furthermore, expression patterns of DnMADS-box genes were investigated during the floral transition process. DnMADS3, DnMADS8 and DnMADS22 were significantly up-regulated in the reproductive phase compared with the vegetative phase, suggesting putative roles of these DnMADS-box genes in flowering. Our data showed that the expressions of MADS-box genes in D. officinale were controlled by diverse exogenous phytohormones. Together, these findings will facilitate further studies of MADS-box genes in Orchids and broaden our understanding of the genetics of flowering.

De novo transcriptome analysis in Dendrobium and identification of critical genes associated with flowering.

Artificial control of flowering time is pivotal for the ornamental value of orchids including the genus Dendrobium. Although various flowering pathways have been revealed in model plants, little information is available on the genetic regualtion of flowering in Dendrobium. To identify the critical genes associated with flowering, transcriptomes from four organs (leaf, root, stem and flower) of D. officinale were analyzed in our study. In total, 2645 flower-specific transcripts were identified. Functional annotation and classification suggested that several metabolic pathways, including four sugar-related pathways and two fatty acid-related pathways, were enriched. A total of 24 flowering-related transcripts were identified in D. officinale according to the similarities to their homologous genes from Arabidopsis, suggesting that most classical flowering pathways existed in D. officinale. Furthermore, phylogenetic analysis suggested that the FLOWERING LOCUS T homologs in orchids are highly conserved during evolution process. In addition, expression changes in nine randomly-selected critical flowering-related transcripts between the vegetative stage and reproductive stage were quantified by qRT-PCR analysis. Our study provided a number of candidate genes and sequence resources for investigating the mechanisms underlying the flowering process of the Dendrobium genus.

[Cough-relieving, analgesic and antibiotic effects of durian shell extracts: a study in mice].

OBJECTIVE: To investigate the cough-relieving, analgesic and antibiotic effects of durian shell extract (DSE) in relieving cough and its analgesic and antibiotic effects. METHODS: The effect of DSE in relieving cough was assessed in mice challenged with ammonia and SO(2) to induce coughing. The analgesic and antibiotic effects of DSE in mice were evaluated by hot plate test and twisting reaction induced by acetic acid, and by minimal inhibitory concentration (MIC) and disc-agar diffusion tests, respectively. RESULTS: Compared with the control group, the mice treated with 300 and 900 mg/kg DSE showed significantly prolonged latency with decreased number of coughing induced by ammonia and SO(2), and the effect was dose-dependent. DSE markedly prolonged the latency and decreased the twisting number of the mice induced by acetic acid without affecting the pain threshold in hot plate test. DSE produced no significant inhibitory effects against Staphylococcus aureus, Staphylococcus epidermidis, or E. coli, and showed a week inhibition against Bacillus aeruginosus. CONCLUSION: DSE shows obvious effect in relieving cough and produces better analgesic effect against chemical factor-induced pain than against physical agent-induced pain sensation. DSE has a moderate inhibitory effect against Bacillus aeruginosus.