阿拉伯芥中兩個E3 RING finger基因之功能性分析及文心蘭C與E MADS box基因RNAi載體之構築

Abstract

E3s RING (Really Interesting New Gene) finger proteins contain a conserved RING motif and play key roles in ubiquitin-mediated proteolysis which has a central role in many processes of plant development. Two RING genes, AtRING9 and AtRING10, were isolated and characterized from Arabidopsis. AtRING9 mRNA is highly expressed in 14-d-old seedling, cauline leaf, flower buds and roots. Further promoter assay by transformed constructs containing AtRING9 promoter fused with report GUS gene indicated AtRING9 is expressed in young leaf, flower buds, SAM (shoot apical meristem), veins and roots. AtRING10 mRNA is expressed in all the organs tested with relatively high expression in seedling, flower buds and roots. Further promoter assay by transformed constructs fused the promoter of AtRING10 with report GUS gene indicated AtRING10 expressed in young leaf, flower buds, SAM and roots. Further analysis indicated that AtRING9 without RING finger domain and the full length of AtRING10 could not enter nucleus by fused with GFP. Ectopic expression of sense and anti-sense for AtRING10 was performed and phenotypic analyzed. The result indicated that sense transgenic plants delayed the flowering time and produced terminal flowers. The anti-sense transgenic plants lost apical dominance and produced curly leaves. These data indicated that AtRING9 and 10 may play roles in regulating SAM activity and controlling the inflorescence development (Chapter 1). MADS box gene played a critical roles in floral organ development. ABCDE model predicts the formation of flower organ by the interaction of five classes of MADS box genes in plant. To generate transgenic flowers with novel phenotype of Oncidium ‘Gower Ramsey ’ with silence of the C (OMADS4) or E (OMADS6、7、11) function genes, RNAi strategy was performed. RNAi construct contained conserved region specific for OMADS4 was constructed. In addition, three conserved regions, specific for OMADS6, 7, 11 respectively, were constructed in the same RNAi construct. Further transformed these constructs into Oncidium in the future will expect to generate transgenic plants with novel flower phenotype (Chapter 2).