UNDERSTANDING THE MODE OF ACTION OF THE NF-YA1 TRANSCRIPTION FACTOR DURING THE MEDICAGO-RHIZOBIA SYMBIOSIS

CAROLINA RÍPODAS; NIEBEL, ANDREAS; LEPAGE, AGNES

Banyuls sur Mer

Encuentro; Plant Adapt 2018; 2018

TULIP

Plants belonging to the legume family are able to interact symbiotically with nitrogen fixing bacteria named rhizobia, allowing these plants to grow in agricultural systems with low nitrogen inputs and thus to be important actors of sustainable agriculture. This symbiotic interaction leads to the formation of a new organ on the roots of the host plants, called the root nodule, inside which atmospheric nitrogen is fixed for the benefit of the plant (Oldroyd, 2013).The nuclear factor YA1 (NF-YA1) is a major regulator of nodule development belonging to the CCAAT-box binding factor family of transcription factors (Baudin et al., 2015; Laporte et al., 2014). The heterotrimeric NF-Y complex is composed of the DNA-binding subunit NF-YA associated with two histone-like subunits NF-YB and NF-YC. In animal systems, NF-Y has been shown to act as both a sequence specific transcription factor, binding CCAAT boxes, but also shows nucleosome-like properties, promoting chromatin accessibility for other master TFs (Oldfield, Yang, & Conway, 2014).With the aim to thoroughly understand the mode of action of NF-YA1 during nodule development, we have performed several synergistic approaches. 1) Identification of target genes using a combination of RNAseq in WT, mutant and over-expressing backgrounds and chromatin immunoprecipitation followed by sequencing (ChIP seq) using NF-YA1-GFP fusions. 2) the epigenetic impact of NF-YA1 as a chromatin modifying TF has been investigated by performing, in WT, and mutant backgrounds ChIP ?Seq analysis using antibodies against active and repressive histone modifications. In addition, chromatin accessibility has been estimated genome wide using an assay for transposase-accessible chromatin using sequencing (ATAC-Seq) approach.