Transcriptomic Characterization of Soybean Roots in Response to Bradyrhizobium Infection by RNA Sequencing

Abstract

Legumes interact with rhizobium convert N2 into ammonia for plant use. To investigate the plant basal nitrogen fixation mechanisms induced in response to Bradyrhizobium, differential gene expression in root of inoculated and mock-inoculated soybean was analysed by RNA-Seq. A total of 55787 transcripts were aligned to soybean genome reference sequences, 280 and 316 transcripts were found to be up-and down-regulated, respectively, in inoculated relative to mock-inoculated soybeans root at V1 stage. Gene ontology (GO) analyses detected 104, 182 and 178 genes associated with cell component category, molecular function category and biological process category, respectively. Pathway analysis revealed that 98 differentiallly expressed genes (115 transcripts) involved in 169 biological pathways. We selected 19 differentially expressed genes and analyzed their expressions in mock-inoculated, inoculated USDA110 and CCBAU45436 using qRT-PCR. The results were consistent with those obtained from rhizobia infected RNA-Seq data. These showed that the results of RNA-Seq have reliability and universality. Additionally, this study showed some novel genes associated with nitrogen fixation process comparison with the previously identified QTLs.