antibiosis

Antibiosis is a biological interaction in which one organism produces effects that harm, inhibit, or kill another organism. It is an antagonistic form of competition that can occur between microorganisms, plants, and animals, and it often involves the release of chemical substances or the exertion of inhibitory mechanisms rather than direct predation.

In microorganisms, antibiosis is well known for the production of antibiotics and bacteriocins that suppress competitors or pathogens. Soil-dwelling bacteria and fungi synthesize secondary metabolites such as penicillins, cephalosporins, and various peptide toxins, which can prevent the growth of rival microbes. Bacteriocins are protein toxins produced by bacteria to inhibit closely related strains. Antibiosis can also occur through non-chemical means, including resource limitation, pH shifts, or enzyme secretion that degrades competing organisms’ extracellular enzymes.

In plants and ecosystems, antibiosis can take the form of allelopathy, where a plant releases chemicals into the environment that inhibit seed germination or growth of nearby plants, microbial communities, or herbivores. In animals, antagonistic interactions can occur through venom or toxins that affect the viability of rivals or prey.

Ecological and applied significance: antibiosis influences community composition, niche partitioning, and the evolution of resistance. It underpins medical and agricultural uses of antibiotics and biocontrol agents, while also contributing to the spread of resistance and environmental impacts when overused. Understanding antibiosis informs studies of microbial ecology, plant ecology, and the development of sustainable pest management strategies.