Overexpression of FT in cotton affects architecture but not floral organogenesis.

Flowering marks the change from indeterminate to determinate plant growth, and this developmental transition involves the activity of the Arabidopsis FLOWERING LOCUS T (FT) gene product and its orthologs. We demonstrated that when FT is ectopically expressed from a viral vector in cotton, a process referred to as virus induced flowering (VIF), it uncouples flowering from photoperiodic regulation and promotes determinate growth in aerial organs. The accelerated switch to determinate growth affected cotton floral buds and sympodial growth, but did not disrupt floral organogenesis. These results can be interpreted in the context of the balance model, which argues that the balance of indeterminate and determinate growth is influenced by the relative abundance of indeterminate and determinate factors in the growing apices. These results emphasize the expanding role of FT in affecting general determinate growth.