Co-inoculation of different antagonists can enhance the biocontrol activity against Rhizoctonia solani in tomato

Biological control by using microbial inoculants is adopted as the best alternative to chemical pesticides to manage plant diseases. In the present study, a microbial consortia based management strategy involving the microbes Bacillus velezensis MB101 (BV), Streptomyces atrovirens N23 (SA) and Trichoderma lixii NAIMCC-F-01760 (TL), was evaluated for the management of Rhizoctonia solani (RS), the causal agent of tomato root rot. The efficacy of these microbial inoculants was evaluated in glasshouse and field experiments. Plant defense-related enzymes were assayed in the glasshouse, and biocontrol effect was evaluated in the field with RS infected soil. In the glasshouse experiment, co-inoculated SA + TL treated plants showed maximum disease resistance in comparison to control. Also, the plant defense-related enzymes such as chitinase, β-1,3-glucanase, peroxidases, polyphenol oxidase, and phenylalanine ammonia lyase were increased in this treatment. Furthermore, three application methods were assessed in the field, and SA + TL showed maximum disease reduction (76%) by the dual application. Based on glasshouse and field study results, it was concluded that co-inoculation of SA + TL activated plant defense against RS as compared to the individual microbes, and co-inoculation could be a new effective strategy to manage the root rot pathogen in an eco-compatible manner.