A microbial consortium in the rhizosphere as a new biocontrol approach against fusarium decline of chickpea

Background and aim Chickpea (Cicer arietinum L.) is an important crop worldwide. Fungi of the genus Fusarium are among the most aggressive pathogens of chickpea, causing plant wilt and/or root rot. The incidence of soilborne pathogens can be reduced by increasing the microbial diversity in the rhizosphere. To improve soil suppressiveness against Fusarium spp., we optimized a microbial consortium consisting in a mixture of bacterial isolates selected from the naturally occurring microflora in the chickpea rhizosphere. Methods Beneficial rhizobacteria were selected based on i) their mutual compatibility when grown in mixture, ii) antagonistic activity against F. oxysporum f. sp. ciceris race 0 and F. solani f. sp. pisi and iii) growth promoting capacity on chickpea. Results The best results were obtained by using a consortium consisting of a mixture of four bacterial isolates: Serratia marcescens isolate 59, Pseudomonas fluorescens isolate 57, Rahnella aquatilis isolate 36 and Bacillus amyloliquefaciens isolate 63. Conclusions This microbial consortium efficiently controlled both Fusarium pathogens, with a consistently higher efficacy compared to those of bacteria applied individually. The putative mechanisms involved in the interaction between antagonists, plant and Fusarium are discussed.