Regulation of Sulfur Sensing by Metabolic Flux Partitioning

Michigan State University, East Lansing MI

Investigators

Abstract

Intellectual Merit: Sulfur is an essential element for all living organisms. Its biological significance is highlighted by the presence of sulfur in essential metabolites and cellular constituents including cysteine, methionine, glutathione, redox centers, sulfolipids, sulfated polysaccharides, and phytoalexins. Sulfur nutrition is thus critical for growth of the organisms and mitigation of diverse stresses. This project aims to elucidate the sulfur sensing mechanisms controlling the regulatory networks for sulfate acquisition and utilization pathways which are essential components for plant biomass production. This project presents a new paradigm of sulfur sensing, which is associated with metabolic flux partitioning of biosynthesis of APS (adenosine 5'-phosphosulfate) and PAPS (3'-phosphoadenosine 5'-phosphosulfate) in two sub-cellular compartments, plastid and cytosol of plants. The primary objective is to identify metabolic flux partitioning of APS/PAPS biosynthesis which is hypothesized as a key switching mechanism for driving transcriptome-wide sulfur responses and plant biomass production. Research will be focused on finding causal relationships between plastid-cytosol partitioning of sulfur assimilation and regulation of sulfur signaling pathways. This project further aims to identify protein-protein interaction networks of APS/PAPS biosynthetic enzymes and their accessory proteins associated with control of sulfur sensing. The long-term goal is to create a quantitative model of sulfur sensing modules in plants. Broader Impacts: This project provides excellent opportunities for students and early career scientists to learn advanced techniques in interdisciplinary areas of biochemistry, molecular biology and omic biology. The education and training activities are based on the frameworks of partnering programs arranged with collaborators sharing common objectives. Participants of the NSF-funded "Plant Genomics@MSU" summer program, which is aimed for training students from under-represented groups, will be accepted in this project as trainees to have research experience in the laboratory. Furthermore, this project will strengthen international collaboration with the EU-funded research training program (Marie Curie Initial Training Network (ITN) "Biochemical and Genetic Dissection of Control of Plant Nutrition (BIONUT)") to obtain expertise in metabolic flux analysis and modeling. This project addresses fundamental questions of nutrient sensing mechanisms and regulation. Discovery of novel components of APS/PAPS biosynthetic enzymes and regulatory coordination of downstream networks will provide novel insights into nutrient sensing mechanisms. The potential link between the sulfur sensing mechanism and biomass production will provide new avenues towards the engineering of plant biomass.