Bioactive Biomolecules from Plant Growth-Promoting Rhizobacteria (PGPR)

Sustainable agriculture techniques to combat abiotic and biotic stresses in eco-friendly approaches are very essential to feed the increased population. Among the plant diseases, fungal pathogens are the biggest global threat causing huge losses in agriculture and food production. Plants and soil microbes interact to help each other for their growth and development. Plants can use the growth-promoting microbes as a weapon against various pathogens including fungi. The PGPR are capable to produce various classes/families of bioactive biomolecules, for example, non-ribosomal polyketide synthases (NRPS), polyketide antibiotics, siderophores, surfactants, hydrolytic enzymes (e.g., protease, lipase, etc.), volatile compounds, etc. By secreting one or more of these bioactive metabolites, the PGPR displays pathogen inhibition. Furthermore, the PGPR can consume nutrients from the soil by scavenging essential micronutrients that are required for the pathogen growth. Hence, these beneficial microbes have great potential application in agriculture, i.e., microbial solution is one of the most eco-friendly alternatives to the extensive use of pesticides and chemical fertilizer to combat fungal crop diseases.