Project description:Orchids are commercially important flowers, comprising one of the largest families of plants. Model plants such as Arabidopsis do not contain all plant genes. In this study, several molecular biology tools were integrated to isolate the flower-specific gene promoters of Oncidium Gower Ramsey (GR). A cDNA library of reproductive tissues was constructed and a microarray was established and used to compare gene expression in flowers and leaves. Five genes were highly expressed in flower tissues and the subcellular locations of the corresponding proteins were identified using fluorescent protein-fusion protein lip transient transformation, and related to their putative functions. BAC clones of the five genes, together with nine previously published flower and reproductive growth specific genes in Onc. GR, were identified and promoter regions were cloned by screening an Onc. GR BAC library. Interestingly, three of the five novel flower-abundant genes were putative trypsin inhibitor (TI) genes, OnTI1, OnTI2 and OnTI3, which were tandemly duplicated in the same BAC clone. Their promoters were identified using transient GUS reporter gene transformation and stable Arabidopsis transformation analyses. In conclusion, a combination of tools including a cDNA microarray, a BAC library, and a bombardment assay can be successfully employed to identify orchid genes and promoters.
