Biocontrol of plant diseases by Bacillus spp.

Biotic stresses significantly threaten worldwide crop production and food security. Rapid, drastic changes in global climate have exacerbated such stresses for crops. Plant diseases are one of the main factors responsible for food crop loss in the world, and 20–40% of such loss is caused by pathogenic infections. Biological control of plant diseases, involving the use of plant associated bacteria or compounds of biological origin, is now considered one of the most promising alternatives to the use of chemical pesticides. In soil and the rhizosphere and endosphere of plants, Bacillus is a predominant bacterial genus, and numerous Bacillus species have been found in many different ecological niches. Bacillus spp. are enormously diverse both metabolically and genetically, which allow them to play an important role in the soil ecosystem, including building biotic stress tolerance in plants. Different members of the Bacillus genus are known to benefit plants by protecting plants from pathogens. Due to this functional versatility, the Bacillus genus is one of the most widely used in the agro-biotech industry. However, the potential of the Bacillus genus has not yet been sufficiently realized, and transferring technology related to the genus from the lab environment to real world applications in the field needs to be emphasized. This review discusses nematodes, fungi, viruses, bacteria, and pest-induced diseases along with the biocontrol attributes of the Bacillus genera and how these attributes can potentially act to increase crop productivity. In addition, this review highlights gaps that remain to be explored to improve and expand on Bacillus-based biocontrol agents that are currently on the market.