Regulation of plant metabolism under elevated CO2
Plant responses to changing environments afford complex regulation at transcriptome and proteomelevel to maintain metabolic homeostasis. Homeostasis itself constitutes a complex and dynamicequilibrium of metabolic reactions and transport processes among cellular compartments. In thepresent study, we aimed at the highest possible resolution of this network by combining analysis oftranscriptome, proteome and subcellular resolved metabolome of plants exposed to rising carbondioxide concentrations over a time course of one week. To prove suitability of our approach, weincluded mutants affected in photorespiratory metabolism and, thus, should deviate from thewildtype in their response to elevated CO2. Our multi-omics analysis revealed that the hpr1-1mutant, defective in peroxisomal hydroxypyruvate reduction, is also affected in cytosolic pyruvatemetabolism, reaching out to cysteine synthesis, while the hexokinase mutant hxk1 displays adisturbed redox balance upon changing CO2 levels. For the third mutant, defective in themitochondrial protein BOU, we found compelling evidence that the function of this transporter isrelated to lipoic acid metabolism, thus challenging current interpretations. This demonstrates thatthe combined omics approach introduced here opens new insights into complex metabolicinteraction of pathways shared among different cellular compartments