Cloning and expression analysis of DnMSI1 gene in orchid species Dendrobium nobile Lindl

WD40 repeat proteins, the homologs of yeast MSI1, are conserved in plants, participating in protein complexes and playing fundamental functions in plant development. Although several MSI1-like proteins have been cloned and characterized in plants, the roles of MSI1-like proteins in the biennial ornamental plant, Dendrobium nobile Lindl, are still unclear. Here, we report the cloning of the DnMSI1 gene from Dendrobium nobile Lindl with RACE technology. We found that DnMSI1 expression was induced by GA₃ and TDZ but inhibited by ABA, PP333, and drought and salt stress. Furthermore, DnMSI1 over-expression in Arabidopsis resulted in decreased tolerance to NaCl stress. These results suggest that DnMSI1 plays negative regulation roles in regulating salinity-stress resistance in Dendrobium nobile Lindl.