Characterization Of An Arabidopsis Late Flowering Mutant

Control of Flowering time is one of the most important physiological activities during the life cycle of plant. Molecular genetic studies on Arabidopsis thaliana revealed four main flowering controlling pathways: photoperiod, vernalization, autonomous, and gibberellin pathway. Although extensive works have been done, the knowledge of flowering time control is also limited. We isolated a late-flowering Arabidopsis mutant, named flx (flowering locus x). In this study, the genetic background of the mutant was "cleaned up" by four rounds of backcrossing to wild type. And the genetic pathway of the FLX in flowering control has been studied.In order to remove extraneous mutations, the flx plants were backcross to their wild-type parents four times. Each time flx is crossed to wild-type, one half of the mutant genome is replaced with wild-type genes. Subsequent analysis of the F₂ population allows the plants that are homozygous for the recessive mutation of interest to be recovered. After four round of backcrossing, the chance of remaining an unlinked secondary mutation is very small. The homozygous flx plants were selected for subsequent study.Then homozygous flx plants (ecotype Columbia) were crossed to wild type plants (ecotype Landsberg), and the resulting F₁ plants were allowed to self-fertilize to generate F₂ population. Late-flowering plants in the F₂ population were selected for mapping.The effect of the photoperiod and vernalization on mutant flx flowering has been studied. The mutant retain photoperiod responses, and the late flowering phenotype was significantly restored by vernalization. These findings suggest that flx is likely accociated with autonomous flowering pathway.