The use of microbial inoculants for biological control, plant growth promotion, and sustainable agriculture: A review

Microbial control agents serve as alternatives to synthetic pesticides for the management of insect pests and plant pathogens. Naturally occurring microorganisms such as bacteria, fungi, and protozoa may be beneficial, pathogenic, or neutral to host plants. This review focuses on the potential role of useful microorganisms as biofertilizers or biopesticides in sustaining and enhancing crop production, and protection. It is necessary to highlight the advantages of the beneficial microorganisms to encourage farmers to use biological control agents and biofertilizers and reduce the excessive use of toxic chemical pesticides and fertilizers. Here, we review the importance of using microorganisms in the agriculture sector for their potential role in fulfilling the nutritional requirements of plants, food safety, and sustainable crop production. Microorganisms can interact with the crop plants to improve their resistance to pathogen attack, plant growth, and development. Their metabolites have been recognized based on their precious excellent plant growth promotion, efficient biocontrol capabilities, successful mass production, appropriate formulation and availability for commercial application. Bio-complexes, including biofertilizers and biopesticides, promote growth and provide protection to plants against various biotic and abiotic stress through the production of plant growth regulators and siderophores, enhancement of nutrient uptake, increasing yield, and production of antagonistic compounds such as antibiotics, hydrolytic enzymes, hydrogen cyanide, and volatile organic compounds. This review sheds the light on the potential of employing microbial agents in agriculture as biofertilizers, biopesticides, nano-biofertilizers and nano-biopesticides to enhance plant productivity and sustainable agriculture.