Characterization of culture‑dependent rhizobial diversity from chickpea nodules interior

Rhizobial inoculum is a feasible and profitable substitute for synthetic nitrogen fertilizer, which is a costly option. The use of rhizobial inoculants has been effective in enhancing crop productivity in developed countries since the late 1800s. However, the lack of a prompt and reproducible protocol to evaluate the competitiveness and efficiency of inoculants under natural field conditions has resulted in a heterogeneous output. Recent developments in synthetic biology and NGS techniques have facilitated the creation of tools to adapt any legume-rhizobial symbiosis for the assessment of nitrogen-fixation efficiency and competitiveness of improved rhizobial inoculum. Additionally, we utilize adaptive laboratory evolution to produce molecular evolution in microbial populations through repeated isolation and reinoculation of rhizobacteria to the same host in specified conditions. Consequently, a rhizobial population with elevated competitiveness and nitrogen fixation efficiency can be selected.