Morphological, Biochemical and Molecular Characterization of Plant Growth Promoting Rhizobacteria with Synergistic Effect against Fusarium oxysporum

Abstract

Currently, plant growth-promoting rhizosphere bacteria (PGPR) are heavily exploited as microbial inoculants in agricultural production among which Pseudomonas sp. and Bacillus sp. are widely used in plant growth promotion and disease control as excellent inoculum strains. Plant growth-promoting rhizobacteria has the potential to be used in agriculture to promote plant growth and health through various mechanisms. Therefore, identifying novel strains tailored to specific agricultural requirements continues to be a key area of research. In the present research work, the strains of PGPR isolated from soybean rhizosphere at Department of Plant Pathology and characterized at morphological, biochemical and molecular level. These strains are now used in ‘Biomix’ formulation a microbial consortium product developed at the Department of Plant Pathology VNMKV, Parbhani to benefit the farmers. Studying the molecular, biochemical, and morphological traits of these microbial strains which are now involved in VNMKV produced ‘Biomix formulation is crucial to maintain its consistency, purity and optimize its formulation. Molecular characterization and phylogenetic analysis will ensure accurate identification and classification of the isolates, enhancing the biofertilizer's effectiveness in agriculture. All three isolates have been identified as per Bergey’s Manual for the determination of bacteriology. All isolates tested positive for starch hydrolysis, citrate utilization, catalase activity, indole production, gelatine hydrolysis, and tetrazolium reduction. Additionally, the 16S rDNA gene sequences of the various potential isolates were validated as P. fluorescens VNMKV1, P. putida VNMKV1, and B. subtilis VNMKV1. The potential of these novel strains of plant growth-promoting rhizobacteria as biocontrol agents was explored by screening against soil-borne pathogenic fungi highlighting their potential to be used as bioinoculant agents.