Flowering Locus T
Overview
Flowering Locus T (FT) is a gene that plays a crucial role in the regulation of flowering time in plants. It is a part of the phosphatidylethanolamine-binding protein (PEBP) family and is highly conserved across various plant species. The FT gene is known to encode a protein that acts as a long-distance signal, or florigen, that travels from leaves to shoot apices to induce flowering.
Function
The FT gene is a key component of the photoperiod pathway, which regulates flowering in response to changes in day length. The FT protein is produced in the leaves in response to certain environmental cues, such as day length and temperature, and then moves to the shoot apex where it induces the transition from vegetative to reproductive growth. The FT protein interacts with other proteins, such as FD and 14-3-3 proteins, to form a complex that activates the transcription of genes necessary for flowering.
Regulation
The expression of the FT gene is regulated by several factors. The CONSTANS (CO) gene is a key regulator of FT. Under long-day conditions, CO protein accumulates in the leaf and activates the transcription of FT. The cryptochromes (CRY) and phytochromes (PHY) are light receptors that regulate the stability and activity of the CO protein. In addition, several other genes, such as FLOWERING LOCUS C (FLC) and FLOWERING LOCUS M (FLM), negatively regulate FT expression.
Role in Crop Plants
Understanding the function and regulation of the FT gene can have significant implications for crop breeding. By manipulating the expression of the FT gene, it is possible to control the flowering time of crop plants, which can be critical for their adaptation to different climates and growing seasons. For example, in rice, the Heading date 3a (Hd3a) gene, which is the rice ortholog of FT, is an important target for breeding early-maturing varieties.