Isolation and Characterization of Terminal Flower1 Homolog Promoter from Precocious Trifoliata Mutant (Poncirus Trifoliata L. Raf.) in Transgenic Arabidopsis

ABSTRACT

The long juvenile phase in woody plants is a serious constraint for traditional or transgenic breeding practices. TERMINAL FLOWER 1 (TFL1) delayed flowering and regulated plant growth through the maintenance of indeterminacy of the shoot apex. To reveal the regulatory mechanism of TFL homolog in poncirus trifoliata L. Raf mutant (PtTFL), a 5'upstream promoter fragment (1 287 bp) was isolated and PtTFL: GUS was constructed and introduced into Arabidopsis thaliana. The result indicated that PtTFL promoter expression showed shoot meristem identity and the activity was positively related with juvenile Arabidopsis before and during plant differentiation phase. Exogenous gibberellins had a complex regulation on the promoter activity. Abscisic acid decreased the promoter activity to 75%, and an ABRE negative regulator “ttaggACGTcagtg” was identified. The behavior of PtTFL promoter activity in short day indicated its correlation with plant development growth. These results may potentially provide a shoot meristem identity promoter in certain developmental stage for genetic engineering.

Keyword:

• Abscisic Acid
• Arabidopsis thaliana
• gibberellins
• TERMINAL FLOWER
• promoter