Compartmentalization and Regulation of Sulfate Assimilation Pathways in Plants

Plants utilize sulfate to synthesize primary and secondary sulfur-containing metabolites required for growth and survival in the environment. Sulfate is taken up into roots from the soil and distributed to various organs through the functions of membrane-bound sulfate transporters, while it is utilized as the primary substrate for synthesizing sulfur-containing metabolites in the sulfate assimilation pathways. Transporters and enzymes for the assimilative conversion of sulfate are regulated in highly organized manners depending on changes in sulfate supply from the environment and demand for biosynthesis of reduced sulfur compounds in the plant systems. Over the past few decades, the effect of sulfur nutrition on gene expression of sulfate transporters and assimilatory enzymes has been extensively studied with the aim of understanding the full landscape of regulatory networks.