Transcriptome Reprogramming in Nodules - An Interaction Between Soybean and Rhizobia

Biological nitrogen fixation (BNF) is a unique feature in legumes such as soybean. This process involves complicated interactions between the plant host and the symbiotic rhizobia, which take place in a unique structure: root nodules. We inoculated soybean with Sinorhizobium fredii and hypothesize that there will be a major transcriptome reprogramming in root nodules, in both soybean and Sinorhizobial cells. The reference genome of soybean is available in public database. To facilitate the bioinformatics analysis of Sinorhizobium fredii, we performed de novo sequencing to obtain full genomes of two Sinorhizobial strains using a combination of single molecule sequencing techniques and other next generation sequencing data. RNA-Seq data were obtained by the Hiseq2000 platform. A total of 1Gb paired end reads for each Rhizobia mRNA samples and 4.5 Gb for W05 (wild soybean) and C08 (cultivated soybean) root and nodule mRNA samples. Filtered reads were mapped to the soybean and sinorhizobial genomes to identify differentially expressed genes in nodules. Some of these differentially expressed genes are located in important pathways relating to the process of BNF.