Abstract
Bolting of lettuce induced by high temperatures is an agriculturally undesirable event, so it is important to reveal the mechanism of the transition from vegetative to reproductive growth in lettuce. The FLOWERING LOCUS T (FT) genes play important role in inducing flowering in several plant species. To understand the floral induction of lettuce, we isolated FT gene (LsFT) from lettuce. Sequence analysis and phylogenetic relationships of LsFT revealed considerable homology to FT genes of arabidopsis, tomato, and other species. LsFT had the potential to induce early flowering in transgenic arabidopsis, but did not affect completely compared with FT of arabidopsis. LsFT mRNA was abundant in the largest leaves in flowering-inducible condition (higher temperature). These gene expressions showed good correlation to the flower differentiation of the shoot apical meristem. Our results indicated that LsFT is putative FT homolog gene in lettuce that regulates flower transition similar to its homolog in arabidopsis. This is the first information of the lettuce floral integrator gene for understanding the regulation of the flower transition in lettuce.
