The uptake of sulfate is under strict metabolic control and driven by the plants sulfur demand for growth and adaptation to the environment. Distinct sulfate transporters are involved in the uptake and distribution of sulfate in plants. At an ample sulfate supply, the Group 1 sulfate transporter Sultr1;2 appears responsible for the primary uptake of sulfate by the root. However, upon sulfate deprivation the sulfate uptake capacity of the root is highly upregulated and in addition Sultr1;2 also Sultr1;1 is highly expressed. In addition to sulfate taken up by the root plants are able to utilize foliarly absorbed H2S as sulfur source for growth, resulting in a decreased sink capacity of the shoot for sulfur supplied by the root. The interaction between atmospheric H2S nutrition and pedospheric sulfate nutrition on the expression of the sulfate transporters Sultr1;1 and Sultr1;2 was evaluated in Brassica pekinensis. The aim of the project is to determine the regulatory signals involved in the expression and activity of the sulfate transporters. The objectives are: i) to assess the in situ regulation of the uptake of sulfate by the root by an integrative physiological and molecular approach viz. transcriptomics and metabolomics analyses, ii) to characterize the signal transduction pathway involved in the cross-talk between sulfate reduction in plastids and the transcription of Group 1 sulfate transporters in the nuclei of cells in the root in relation to the sulfur demand for growth and supply, e.g. sulfur deprivation, development for the regulation of expression and activity of the Group 1 sulfate transporters in relation to the sulfur demand for growth and supply, iv) to further establish the shoot-root-shoot signaling in regulation of sulfate transporters in roots of Brassicaceae in relation to sulfur demand and supply.
