CLONING AND EXPRESSION ANALYSIS OF A VRN1-LIKE GENE FROM DENDROBIUM NOBILE

Effects of thidiazuron (TDZ) on flowering of Dendrobium nobile were investigated, by spraying on leaves with a concentration of 20mg/L; and to further investigate the molecular mechanism of the process, theVRN1-like gene was cloned from protocorm-like bodies (PLBs) of Dendrobium nobile , the effects of cytokinins on its expression in axillary buds and PLBs were studied using semi-quantitative RT-PCR analysis. The results showed that flowering of D. nobile could be induced by application with TDZ instead of cold; the full-length cDNA of a VRN1-like gene named DnVRNA (GenBank accession No. EF535598) was cloned, which encodes a peptide with 63% and 62% similarity to the VRN1 protein from Festuca arundinacea and Triticum monococcum, respectively. Semi-quantitative RT-PCR analysis showed that the expression of DnVRNA in axillary buds was improved by TDZ, and those in PLBs were also up-regulated by cytokinins and cold, which suggesting that it would function in cytokinin-induced floral transition.