Antibiosis
The process of antibiosis refers to an interaction between two organisms, in which the growth and/or the activity of one organism is inhibited by the other organisms via the production of chemical compounds. A wide variety of chemical compounds could be involved in this process, including antimicrobial substances, bacteriocines, fungistatic compounds, surfactants, enzymes (e.g., chitinolytic, etc.). Bacteria and fungi are the main actors responsible for the production of antibiotic and antagonistic compounds, and this process is mainly active against other microorganisms.
Antibiosis is only considered under the Disease and Pest Management function. Through antibiosis, microbially produced antibiotics are ultimately able to control plant pathogens and pests, and the damage they might cause to plants. Some antibiotics and secondary metabolites produced by microorganisms are used against other microorganisms and can also activate induced resistance in the plants, and/or inhibit other non-target organisms.
Antibiosis can be estimated by measuring microbial antibiotic activity with lab-based functional antibiosis bioassays[1],[2], or with the agar well diffusion assay[3],[4]. Antibiosis can also be assessed through the measurement of enzymatic activities such as chitinolytic activity[3]. Other methods rely on molecular quantification of functional genes and transcripts involved in antibiotic production with qPCR and RT-PCR, respectively[5],[6].
[1] de Corato U et al. 2018. Suppression of soil-borne pathogens in container media amended with on-farm composted agro-bioenergy wastes and residues under glasshouse condition. Journal of Plant Diseases and Protection 125: 213–226.
[2] Dundore-Arias JP et al. 2020. Carbon Amendments Influence Composition and Functional Capacities of Indigenous Soil Microbiomes. Frontiers in Molecular Bioscience 6.
[3] Idris HA et al. 2008. Suppression of Pythium ultimum root rot of sorghum by rhizobacterial isolates from Ethiopia and South Africa. Biological Control 45: 72-84.
[4] Tagg JR and McGiven AR. 1971. Assay system for bacteriocins. Applied Microbiology 21: 943.
[5] Imperiali N et al. 2019. Relationships between Root Pathogen Resistance, Abundance and Expression of Pseudomonas Antimicrobial Genes, and Soil Properties in Representative Swiss Agricultural Soils. Frontiers Plant Science 29.
[6] De Coste NJ et al. 2010. Verticillium dahliae alters Pseudomonas spp. populations and HCN gene expression in the rhizosphere of strawberry. Canadian Journal of Microbiology 56: 906-915.