Methylome analysis reveals an important role for epigenetic changes in the regulation of the Arabidopsis response to phosphate starvation

Phosphate (Pi) availability is a significant limiting factor for plant growth and productivity in both natural and agricultural systems. To cope with such limiting conditions, plants have evolved a myriad of developmental and biochemical strategies to enhance the efficiency of Pi acquisition and assimilation to avoid nutrient starvation. In the past decade, these responses have been studied in detail at the level of gene expression; however, the possible epigenetic components modulating plant Pi starvation responses have not been thoroughly investigated. Here, we report that an extensive remodeling of global DNA methylation occurs in Arabidopsis plants exposed to low Pi availability, and in many instances, this effect is related to changes in gene expression. Modifications in methylation patterns within genic regions were often associated with transcriptional activation or repression, revealing the important role of dynamic methylation changes in modulating the expression of genes in response to Pi starvation. Moreover, Arabidopsis mutants affected in DNA methylation showed that changes in DNA methylation patterns are required for the accurate regulation of a number of Pi-starvation-responsive genes and that DNA methylation is necessary to establish proper morphological and physiological phosphate starvation responses.