Molecular characterization of FLOWERING LOCUS T(FT)genes from bamboo (Phyllostachys violascens)

Bamboos are versatile multipurpose forest products that are so important economically that they are often referred to as green gold. With the development of modern gardens, bamboos have become one of the main garden plants because of their unique aesthetic beauty. However, flowering usually causes bamboo to die. To explore the genetic and molecular mechanisms that underlie the transition from the vegetative to reproductive stage in bamboos, two FT-like genes, PvFT1 and PvFT2, were identified in a bamboo species (Phyllostachys violascens). The cDNA sequences of PvFT1 and PvFT2 consisted of 962 bp and 890 bp, respectively, and each encodes 178 amino acids. These two proteins belonged to the PEBP family and contained a Tyr residue that is critical to differentiate FT and TFL1. Like other florigen, PvFT1 is expressed only in the leaves and reached its highest level 20 to 30 days before flowering. It's transcript is not detected in those plants that never flowered, while PvFT2 mRNA is observed only in spikelet. PvFT1 transcript accumulation was diurnally expressed with a peak at dusk. Constitutive expression of full-length PvFT1 in rice cause early flowering relative to wild-type and in vitro, 50 % of shooting plants displayed structures that resembled floral organs. Our results suggested that PvFT1 might be a candidate gene for florigen and played a role in the induction of bamboo flowering, while PvFT2 might be involved in the development of floral organs. This information could lead to a better understanding of the mechanisms involved in bamboo flowering.