Characterization of an Arabidopsis E3 RING finger geneand an Orichid (Oncidium Gower Ramsey) CONSTANS (CO)-like gene in regulating plant development and flowering

• Main Authors: Chai-Wei Kao, 郭家緯
• Other Authors: 楊長賢
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/77578186082348147869

碩士 === 中興大學 === 生物科技學研究所 === 95 === ABSTRACT Plant development is regulated by many genes and pathways from embryotic phase, vegetative phase to reproductive phase. RING genes that contained a RING finger motif as E3 function have been thought to be involved in ubiquitination pathway in regulating plant development. AtRING5 with conserved RING domain encoded a 493 amino acid protein was identified in Arabidopsis. To further investigate AtRING5 function, promoter assay and transgenic approaches were used. Promoter assay by transforming constructs fusing the promoter of AtRING5 with report GUS gene in Arabidopsis indicated that AtRING5 was expressed in young shoot and root meristem and its expression was decreased during late stage of organ development. Furthermore, GUS was detected in the meristem of the newly formed lateral roots in Arabidopsis after IAA induction. These results indicated that AtRING5 may be a regulator in controlling the meristem formation. Transgenic plant that ectopic expressed sense, antisense and RNAi (RNA interference) of AtRING5 resulted in the alteration of inflorescence differentiation, cotyledon formation, root morphology and root hair development. This data supported that AtRING5 is functioning in regulation of meristem formation during early development stage. Many pathways regulated the flowering transition including circadian clock associated genes such as GI and CO (CONSTANTS) which play a mediated role in photoperiodic pathway of Arabidopsis. CO has been thought to activate its target gene FT (Flowering locus T) to promote the flowering in LDs. In this study, CO-like genes were cloned and characterized from Oncidium Gower Ramsey and Eustoma grandiflorum. The expression of Oncidium OnCOL1 that encoded a 328 amino acids protein was induced by dark treatment. In 35S::OnCOL1 transgenic Arabidopsis plants, acceleration in flowering time was observed. In addition, three CO-like genes, EgCOL1 and 3 encode proteins of 369 and 320 amino acid residues and EgCOL2 with 517 bp partial DNA sequence were cloned from E. grandiflorum. Constructs contained EgCOL genes were constructed for further functional analysis through transgenic approach in both Arabidopsis and E. grandiflorum.