FUNCTIONAL GENOMICS OF LEGUME MICROBIAL ENDOSYMBIOSIS

¹ Max Planck Institute of Molecular Plant Physiology

Symbiotic nitrogen fixation (SNF) between legumes and rhizobia requires differentiation and integration of both plant and bacterial metabolism. Transcriptome and metabolome analyses were carried out to obtain the first global, non-biased overview of plant metabolism in mature root nodules of Lotus japonicus containing Mesorhizobium loti. Using cDNA arrays to measure relative transcript levels of over 2000 different nodule-expressed plant genes, we identified 870 genes that were induced more that 2-fold (P<0.05) in mature nodules compared to un-inoculated roots of 7 week old plants. Transcriptome analysis revealed co-ordinate up-regulation of a number of important metabolic pathways in nodules, and provided novel insight into physiological conditions that may prevail within nodules. These results were supported by metabolome analysis using GC-MS.