Bioprospecting of microbial isolates from biodynamic preparations for PGPR and biocontrol properties

Abstract

Aim: To study the role of microorganisms behind their bioenhancing, biocontrol properties, their enzymatic potential, and characterization of high performing microbial isolates on molecular basis. Methodology: Dominant culturable microbes including bacteria and fungi were isolated from biodynamic preparations and screened on the basis of plant-growth promoting (PGP) activities viz., ammonia production, phosphate solubilization, siderophore production, hydrogen cyanide production, seed germination efficacy and biocontrol properties. The dominant and effective microorganisms were screened for enzymes activities viz., pectinase, cellulase and amylase. The selected bacterial and fungal isolates, exhibiting higher enzyme activities, were subjected to molecular characterization. Results: Out of 68 bacterial and 25 fungal isolates from 8 biodynamic preparations (BD 500 - BD 507), 15 bacterial isolates exhibited high plant growth promoting activities while 10 bacterial isolates exhibited biocontrol activity against pathogens. Bacillus licheniformis isolated from BD 504, expressed high pectinase (2.595 U ml-1 min-1), cellulase (0.308 U ml-1 min-1) and amylase (0.418 U ml-1 min-1) activities. Fungal isolates with high enzymatic activities, were isolated from BD 500, 503 and 506, respectively. Interpretation: Microorganism isolates from biodynamic preparations possessed strong plant growth promoting, biocontrol and enzymatic properties, which might be responsible for the efficacy of organic preparations under field conditions.

Effectiveness of a single and a mixture treatments of rhizobacteria in increasing the growth and yield of hot pepper (Capsicum annuum L.)

“…The role of rhizobacteria as PGPR is generally related to their ability to produce growth hormone [6,7], nitrogen fixation [8], or dissolve phosphate [9,10]. Meanwhile, the role of rhizobacteria as pathogenic antagonist agents is IOP Publishing doi:10.1088/1755-1315/977/1/012044 2 related to their ability to produce antibiotic compounds, siderophores, hydrogen cyanide (HCN), and secrete extracellular enzymes [11][12][13][14][15].…”