How does Flowering locus T2 work in poplar? Shedding light on its novel functions

FT (Flowering locus T) is one of the main factors involves in the control of the photoperiodic signalling that regulates important developmental transitions such as flowering or growth-dormancy cycles in annual and perennial plants. In this work we generated and studied poplar FT2 loss of function lines using the CRISPR/Cas9 technology.

Our studies provide crucial information in the understanding of how FT2 works in poplar trees:

- In apical buds, FT2 is essential to maintain the vegetative growth (Figure A).
- FT2 plays a role regulating the optimal internode growth of the elongation zone (Figure A).
- FT2 acts upstream of the gibberellin pathway in both apical buds and leaves to control growth (Figure B).

We finally propose a functional model of FT2, promoting apical growth and limiting internode elongation in poplar trees, through modulating GA 13-hydroxylation pathway (Figure C).