Phosphate starvation induces DNA methylation in the vicinity of cis-acting elements known to regulate the expression of phosphate–responsive genes

Abstract

Phosphate (Pi) limitation is a constraint for plant growth in many natural and agricultural ecosystems. Plants possess adaptive mechanisms that enable them to cope with conditions of limited Pi supply, including a highly regulated genetic program controlling the expression of genes involved in different metabolic, signaling and development processes of plants. Recently, we showed that in response to phosphate limitation Arabidopsis thaliana sets specific DNA methylation patterns of genic features that often correlated with changes in gene expression. Our findings included, dynamic methylation changes in response to phosphate starvation and the observation that the expression of genes encoding DNA methyltransferases appear to be directly controlled by the key regulator PHOSPHATE RESPONSE 1 (PHR1). These results provide insight into how epigenetic marks can influence plant genomes and transcriptional programs to respond and adapt to harsh conditions. Here we present an analysis of DNA methylation in the upstream regions of low Pi responsive genes in Arabidopsis seedlings exposed to low Pi conditions. We found that hypo- and hyper-methylation in the vicinity of cognate binding sites for transcription factors known to regulate the phosphate starvation response clearly correlates with increased or decreased expression of low-Pi responsive genes.