One health, one soil

Interconnecting soil, microorganisms and ecosystem health in one health concept 

Understanding the “one health” concept 

The “one health” concept illuminates a profound interconnectedness between human health and the broader ecosystem. This holistic approach recognizes that the well-being of humans is intrinsically linked to the health of soil, plants, animals, and their microbial communities. 

Microbial communities are critical to the one health concept because they facilitate cross-ecosystem interactions, regulate biological processes, serve as biological indicators of environmental health, and mediate complex interactions between humans, animals, and the environment. 

Soil as a source of microbial diversity 

Recent research by Banerjee et al. (2023) underscores the critical role of soil as a central element in the one health framework. Soils serve as complex reservoirs of extensive microbial diversity hosting pathogens and beneficial microorganisms. 

There are plentiful microorganisms in soil, they constitute the largest component of global biomass on Earth: 

• bacteria- 15% of the total living biomass, 

• fungi- 2% of the total living biomass, 

• archaea- 1% of the total living biomass. 

Microbiome diversity in soil, animals, and human body

Soil microbiome 

Soil represents a complex, dynamic microbial ecosystem with superior biodiversity. As a primary reservoir of microorganisms, it harbors an intricate network of bacterial, fungal, and other microbial communities that play crucial roles in ecological processes. 

The soil and rhizosphere ecosystem is incredibly diverse, primarily inhabited by Pseudonadota, Actinomycetota, Cyanobacteria, and Acidobacteriota. 

Bulk soil contributes over one-third of the bacterial and fungal diversity present in plant endophytic microbiota.

Functional significance of soil microbiome:

1. Nutrient cycling

In nutrient cycling, soil microorganisms break down complex organic materials into simpler forms that plants can utilize. They decompose plant residues, animal waste, and other organic matter, releasing essential nutrients into the soil. The transformation of nitrogen represents one of their most crucial functions, where specialized bacteria convert atmospheric nitrogen into plant-available forms through biological nitrogen fixation. Similarly, microorganisms play vital roles in phosphorus solubilization and carbon cycling, making these essential elements available for plant uptake and ecosystem function.

2. Soil structure maintenance

Through the production of extracellular compounds and the physical networking of fungal hyphae, microorganisms help bind soil particles together into stable aggregates. The resulting soil stability also helps prevent erosion, maintaining the integrity of the soil system and its ability to support plant life.

3. Plant health support

The relationship between soil microbes and plant health represents a fascinating example of evolutionary cooperation. Beneficial microorganisms, particularly mycorrhizal fungi and plant growth-promoting rhizobacteria, form intimate associations with plant roots, facilitating nutrient uptake and producing compounds that stimulate plant growth and development.

4. Pathogen regulation

In terms of disease suppression, soil microorganisms form a critical first line of defense against plant pathogens. Through various mechanisms including competition for resources, production of antimicrobial compounds, and induced systemic resistance in plants, beneficial microbes help maintain plant health by preventing the establishment and proliferation of harmful organisms.

5. Climate change resilience

The role of soil microorganisms in climate change resilience has gained increasing attention as we face global environmental challenges. These microscopic organisms influence greenhouse gas dynamics through their involvement in carbon sequestration and nitrogen cycling processes. Their activities can contribute to or mitigate greenhouse gas emissions, depending on environmental conditions and management practices. Additionally, robust soil microbial communities support ecosystem recovery following disturbances, helping maintain ecological stability in changing environmental conditions.

Human microbiome 

Human gut microbiota demonstrate less diversity, primarily composed of Bacillota, and Bacteroidota. 

The functional significance of animal microbiome concentrates on immune system regulation (modulate inflammatory responses, develop immune system tolerance) metabolic contributions (digest complex nutrients, produce essential vitamins), and physiological interactions (gut-brain axis communication, endocrine system modulation).

Animal microbiome

Animal microbiomes exhibit relatively higher diversity, with a significant presence of Pseudonadota. 

The functional significance of animal microbiome concentrates on digestive functions (nutrient breakdown, vitamin synthesis), immune system modulation (pathogen defense, inflammatory response regulation), metabolic regulation (hormone balance, glucose metabolism), neurological interactions (neurotransmitter production, gut-brain axis communication), species adaptation (environmental resilience, nutritional optimization). 

Conclusion

Research has shown that the microbiomes of soil, plants, and humans are more interconnected than previously understood. Scientists have identified specific microbial groups that cross traditional ecosystem boundaries. 

The soil microbiome has many functions that support the health of humans, animals, and plants.

Microbiome transfer pathways: 

• soil microbes influence plant and animal health, 

• plant microbiomes impact agricultural productivity, 

• human and animal gut microbiomes interconnect through environmental exposures. 

The scientific community concludes that developing advanced monitoring tools to investigate soil microbiome composition and stability should be a strategic priority in advancing our understanding of one health principle.

Source: The link between soil, plant, animal and human microbiomes (credits: Benerjee et al. 2022; Nature Reviews Microbiology).