Competition
During the process of competition, organisms compete for the same resources and the outcome usually has negative effects on the weaker competitors. The resource for which the organisms compete can include nutrients (e.g., carbon, iron) as well as space (e.g., root surface, plant tissue). Competition also refers to the consumption of pathogen stimulatory compounds, the extracellular degradation of antagonistic compounds and interference with their production. Bacteria and fungi are the main contributors to this process in soils, and they are mainly active against other microorganisms.
Competition is considered under the Disease and Pest Management function only. Through competition for resources, microorganisms are ultimately able to control plant pathogens and pest and the damages they might cause to plants.
Competition can be estimated by measuring microbial competitive activity with lab-based functional bioassays[1],[2] or the measurement of compounds involved in the competition such as siderophores [3] . Other methods rely on molecular quantification of functional genes and transcripts involved in antibiotic production with qPCR and RT-PCR, respectively[4],[5].
[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] Schwyn & Neilands. 1987. Universal chemical assay for the detection and determination of siderophores. Analytical Biochemistry 160: 47-56.
[4] 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.
[5] 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.