Differential plant growth-promoting rhizobacteria species selection by maize, cowpea, and lima bean

Plant growth-promoting rhizobacteria (PGPR) are an important component of the complex rhizosphere micro -biome. It is often reported that the rhizosphere of different plant species selects their PGPR community, which promotes the growth of some more than others. In this greenhouse study using the same agricultural soil, we assessed the PGPR community in the rhizosphere of important plant species, including two cultivars (maize and cowpea) and one landrace (lima bean). The PGPR community structure differed between the rhizosphere the landrace and the cultivars, which presented similar community structures. The rhizosphere of lima bean showed exclusive PGPR groups (Streptomyces, Soliruborbacter, and Methylobacter), which are involved in resistance and stress tolerance in plants. The rhizosphere of both cultivars presented a similar relative abundance of Bacillus and Paenibacillus, groups involved in plant growth promotion by the production of antibiotics and biological N fix-ation. In addition, the cultivars presented more proportion of specialist microbes, and the community interaction was more complex than the landrace. The findings of this study expand the knowledge of the PGPR community in distinct plant species and confirm the significant effect of landraces and cultivars on rhizobacteria community selection.