LDL1 and LDL2 histone demethylases interact with FVE to regulate flowering in Arabidopsis

In higher plants, epigenetic modifications provide a stage for both transient and permanent cellular reprogramming required for vegetative to reproductive phase transition. Arabidopsis LSD1-like 1 (LDL1), a histone demethylase positively regulates floral transition, but the molecular and biochemical nature of LDL1 mediated flowering is poorly understood. Here we have shown that LDL1 mediated regulation of flowering is dependent on MADS AFFECTING FLOWERING 4 (MAF4) and MAF5 floral repressors. LDL1 binds on the chromatin of MAF4 and MAF5 and removes H3K4me2 activation marks to repress their expression. Further we show that LDL2 negatively regulates the expression of MAF4 and MAF5 redundantly with LDL1. Both LDL1 and LDL2 interact with an autonomous flowering pathway protein, FLOWERING LOCUS VE (FVE), to regulate the floral transition and thus could be a part of the FVE-corepressor complex. We show that MAF5 interacts with other floral repressors FLC and SHORT VEGETATIVE PHASE (SVP) and repress the expression of FT to delay floral transition. Thus, our results deepen the mechanistic understanding of LDL1/LDL2-FVE mediated floral transition in Arabidopsis.