Yang, Chang-Hsien .
Functional Analysis and Characterization of B Functional MADS Box Genes form Orchid (Oncidium Gower Ramsey).
MADS box genes controlled many important developmental processes in plant. Most ABCDE class genes regulating flower formation are MADS genes that contained a DNA-binding domain (MADS box domain) and a protein interaction domain (K domain) in their proteins. To investigate the flower formation in orchid, three B class MADS box genes, OMADS5, OMADS8 and OMADS9, were isolated and characterized from Oncidium Gower Ramsey in this research. OMADS8 encoded a 210 amino acid protein showed high sequence homology to Arabidopsis B class gene PI. OMADS8 is expressed in all the organs tested including leaf, root and flower. In flowers, OMADS8 mRNA was especially detected higher in the sepal, petal and lip than in stamen and carpel. Ectopic expression of OMADS8 significantly reduced the plant size and promoted flowering time in transgenic Arabidopsis. The conversion of sepal to petal-like structure was also observed in 35S::OMADS8 transgenic plants. OMADS5 and OMADS9 encoded proteins showed sequence homology to PaleoAP3 lineage of B group MADS box gene such as DcOAP3B in Dendrobium and PeMADS3 in Phalaenopsis. In their C-terminal region, two completely consensus motifs such as PI-derived and PaleoAP3 motifs which are unique to B class gene of monocots were identified. OMADS5 is expressed in sepal and petal whereas OMADS9 is expressed in petal and lip in flowers. The alternation of flower organs also observed in transgenic Arabidopsis ectopically expressing OMADS5 or OMADS9. Furthermore, to investigate the interaction among the Oncidium B class proteins, yeast two hybrid analysis was performed. The result indicated that OMADS5 and OMADS9 were able to form homodimers and heterodimers to each other.
Log in to add this item to your schedule
1 - National Chung Hsing University, Graduate Institute of Biotechnology, Taichung, 40227, Taiwan
MADs box genes
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM