Metabarcoding of bradyrhizobial populations using genus-specific partial 16S-23S rDNA ITS

Bradyrhizobium genus belongs to the alphaproteobacteria family. Bacteria belonging to this large and diverse taxonomical group are recovered from most biomes. Many species and strains belonging to this genus can also develop nitrogen fixing symbioses with a broad range of leguminous plants. Even though symbiotic bacteria can be easily isolated from root nodules and genotyped, the advances of NGS technology and affordable prices can now also be used to estimate the diversity and evaluate the relative abundances of nitrogen fixing rhizobia associated to symbiotic plants. With the objective to develop a specific marker that would be suitable for the study of bradyrhizobia diversity through illumina MiSeq based high throughput sequencing, a genus specific region included in the 16S-23S RNA internal transcribed spacer (ITS) sequence was selected and used to study the composition of bradyrhizobial populations associated to the whole plant root system in cowpea and peanut.