Holobiont in an agroecological vision
Holobiont in an agroecological vision
A holobiont is the functional ensemble consisting of a multicellular host organism and all the communities of microorganisms that live in stable association with it (bacteria, archaea, fungi, protists, and viruses), considered as a single biological and ecological unit.
From this perspective, the host organism is not viewed as an isolated entity, but as part of an integrated system; the associated microorganisms (the microbiota) contribute to key functions such as metabolism, development, immunity, and environmental adaptation; furthermore, the combined genomes of the host and symbionts are sometimes called the hologenome.
The concept of the holobiont is particularly important in evolutionary biology, ecology, and medicine because it suggests that natural selection can act on the host-microbiota unit, and not just on the individual organism.
Within the field of agroecology, a holobiont is a complex biological unit consisting of a host organism (such as a cultivated plant) and its associated microorganisms and symbionts, considered as an integrated functional system. It is therefore a concept that views the host and its microbiota as a single ecological organism, whose vital functions—growth, stress resistance, and productivity—emerge from the interactions between all its components.
The health and productivity of the host depend not only on the microbiota (bacteria, fungi, mycorrhizae, beneficial nematodes) but also on interactions with other biocoenoses of the agricultural ecosystem: pollinating and predatory insects, birds and wildlife that regulate pests, and the soil complex, which includes organic matter, decomposing microorganisms, and available nutrients. Recognizing plants as holobionts means adopting agricultural practices that promote biodiversity at multiple levels, stimulate natural ecological interactions, and reduce dependence on chemical inputs, improving the resilience of agroecosystems and overall sustainability.
In practice, this approach involves concrete actions such as:
– Soil and microorganisms: use of compost, crop rotations, and cover crops to promote mycorrhizae, beneficial bacteria, and beneficial nematodes.
– Insects and pollinators: installation of hedges, wildflowers, and habitats for predatory insects and pollinators.
– Birds and wildlife: preservation of refuges and ecological corridors for natural pest predators.
– Multiple interactions: combining these strategies to strengthen ecological networks that support nutrition, plant health, and natural pathogen control.
Conclusions and practical applications
Recognizing plants as holobionts changes agricultural management.
Viewing the plant as an integrated unit with its microbiota and surrounding biocoenoses leads to a holistic approach to cultivation. Health and productivity no longer depend solely on plant genetics, chemical fertilizers, or other external inputs, but on the interactions between organisms and microorganisms present in the agricultural ecosystem. Below are some of the many examples of how agricultural productivity can be managed using the holobiont concept.
Improving soil fertility and health
Practices such as the use of compost, mature manure, crop rotations, and cover crops encourage the proliferation of mycorrhizae, beneficial bacteria, and beneficial nematodes. These microorganisms improve nutrient uptake and plant resistance to stress, reducing the need for chemical fertilizers and promoting a more vibrant and resilient soil.
Promoting Biological Control and Pollination
Creating habitats for pollinating insects and natural predators, through hedges, wildflowers, or plant borders, supports natural ecological networks that regulate pests and increase crop productivity without chemical pesticides.
Conserving Wildlife as Part of the Agroecosystem
Maintaining ecological corridors and refuges for birds and other natural predators promotes the biological control of pathogens and pests, integrating the functions of the microbiota with those of broader biocoenoses.
Integration and Synergy between Agroecological Practices
The effectiveness of strategies based on the holobiont concept increases when practices are combined: fertile soil, a balanced microbiota, and animal and plant biodiversity. This synergistic approach improves the resilience of agroecosystems, increases production stability, and reduces environmental impact.