A cytokinin route to flowering in Arabidopsis

Abstract

Cytokinins (CKs) are involved in many physiological processes. We observed that the application of N6-benzylaminopurine (BAP) to the roots of hydroponically grown plants of Arabidopsis thaliana promotes flowering in non-inductive short days. The response to BAP treatment does no require FLOWERING LOCUS T (FT), but activates its paralogue TWIN SISTER OF FT (TSF), as well as FD and SUPPRESSOR OF OVEREXPRESSION OF CO1 (SOC1) (D'Aloia et al., 2011). We present here complementary data obtained with transgenic plants overexpressing a catalytic CK OXIDASE/DEHYDROGENASE (CKX) in the roots. The high efficiency of BAP in promoting flowering in our experimental system contrasts with the variability that emerges from studies gathered in literature. Many factors, either experimental or inherent to plant material, might explain these discrepancies and we are interested in identifying endogenous regulators that might provide a mechanistic explanation. We are therefore investigating whether the endogenous pathways underlying plant developmental phase changes might regulate the relative contribution of CKs to flowering