Characterization of Potential Plant Growth Promoting Rhizobacteria Isolated from Maize (Zea maysL.) in Central and Northern Benin (West Africa)

Abstract

Our study aims to characterize Plant Growth Promoting Rhizobacteria (PGPR) isolated from maize roots in five agroecological zones of central and northern Benin. Sixty samples were collected at the rate of four samples per village and three villages per agroecological zone. Rhizobacteria strains were isolated from these samples and biochemically characterized. These strains were analyzed for some of their PGPR traits like ammonia production and hydrogen cyanide following conventional methods. Microbiological investigation of these samples has shown that maize rhizospheres in central and northern Benin contain a high diversity of microorganisms. A total of nine species of maize Plant Growth Promoting Rhizobacteria were identified. Those PGPR include fiveBacillusspecies (B. polymyxa, B. pantothenticus, B. anthracis, B. thuringiensis, andB. circulans), threePseudomonasspecies (P. cichorii, P. putida, andP. syringae), andSerratia marcescens. The microbial diversity does not depend on the soil types. The microbial density, generally high, varies according to both soil types and agroecological zones. AllSerratiastrains (100%) have produced ammonia, whereas 80% ofBacillusand 77.77% ofPseudomonasproduced this metabolite. The hydrogen cyanide was produced by all isolates (100%) independent of their genus. These results suggest the possibility to use these rhizobacteria as biological fertilizers to increase maize production.