39:	Late-flowering genes interact with early-flowering genes to regulate flowering time in Arabidopsis thaliana.

Authors:	Chou, Ming-Lun(A)Yang, Chang-Hsien(A)
Affiliations:	(A): Graduate Institute of Agricultural Biotechnology, National Chung Hsing university, Taichung, Taiwan, ROC
Presenter:	Yang, Chang-Hsien , chyang@dragon.nchu.edu.tw

The transition from vegetative rosette to reproductive inflorescence has been extensively studied in Arabidopsis. Many mutations defective in genes involved in either delaying or promoting the timing of the rosette-to-inflorescence transition have been identified. Although they caused similar mutant phenotype, different late-flowering mutants characterized so far respond to enviromental stimuli differently. To investigate the genetic mechanisms regulating the transition from vegetative to reproductive phase in Arabidopsis, double mutants between three different early-flowering mutants, early flowering 1, 2, 3 (elf1, 2, 3) and five different late-flowering mutants, gi-1, ft-1, fwa-1, ld-1, and fca-9, were generated and the phenotypes analyzed. Double mutants in all combinations displayed the late-flowering phenotypes resemble to their respective late-flowering parents in both flowering time and the number of vegetative leaf produced. The result indicates that five late-flowering mutants are epistatic to all three early-flowering mutants tested here. This epistasis relationship suggests that ELF1, ELF2, and ELF3 genes function upstream of these five late-flowering genes no matter they are functioning in autonomous or photoperiod pathways. These three early-flowering genes may negatively modify the activity of most late-flowering genes to influence the time of the vegetative-to-reproductive transition in Arabidopsis.