Biocontrol potential of Bacillus gibsonii and Brevibacterium frigoritolerans in suppression of Fusarium stalk rot of maize: a sustainable approach

Natural interactions between plant and associated microbes have vital importance in plant growth and vigor. Plant growth promoting rhizobacteria (PGPR) modulates growth promotion and suppression of plant diseases. Maize (Zea mays L.) being an important cereal crop faces loss in annual yield due to stalk rot caused by fungal pathogen Fusarium moniliforme. Native bacteria can be used to reduce fungal disease and could provide a sustainable solution to reduce yield loss by pathogen attack. Two antagonistic PGPR, Bacillus gibsonii and Brevibacterium frigoritolerans were investigated for their potential to enhance growth and ameliorate the negative effects of F. moniliforme on both diseased effected and normal plants. Two maize varieties TP-1217 (Variety A) and TP-1221 (Variety B) were subjected to different treatments under greenhouse conditions by using a completely randomized design. Analysis of plant growth parameters, chlorophyll and proline contents, electrolyte leakage, antioxidant enzyme activities, and disease index assessment was done to examine the induced tolerance and plant growth promotion by applied PGPR. Results indicated potential antifungal activity of bacterial strains. Inoculation of bacterial strains to plants reduced disease and enhanced plant growth parameters. Disease suppression was influenced by 67% and plant growth was enhanced significantly. Relative electrolyte leakage reduced by 52 -55% and more than 80% disease control in both varieties of the plant was observed. Application of bacteria as biocontrol agents in combination with current disease protection strategies could aid in global food security.