How Adding Biochar Affects Soil Health and Antibiotic Resistance in Plants

Jenn Hoskins
8th August, 2024

How Adding Biochar Affects Soil Health and Antibiotic Resistance in Plants

Image Source: Natural Science News, 2024

Key Findings

  • A study by Zhejiang University found that adding biochar to soil significantly reduced antibiotic resistance genes (ARGs) in plant tissues
  • Biochar reduced ARGs in plant root and leaf endophytes by 1.2-2.2 orders of magnitude, but had no significant effect on ARGs in soil and rhizosphere samples
  • The study suggests biochar can improve food safety by reducing ARGs in plants, though it may not fully address ARGs in soil
Antibiotic resistance is a critical global health issue, exacerbated by the interconnectedness of human, animal, and environmental health. This complexity is highlighted by the One Health approach, which emphasizes the interconnectedness of these domains in the spread and evolution of antibiotic resistance[2]. A recent study conducted by Zhejiang University explores a promising strategy to mitigate antibiotic resistance genes (ARGs) in soil and plants using biochar amendment[1]. Biochar, a carbon-rich product derived from organic material, has been investigated for its potential to reduce ARGs in agricultural settings. The study conducted field trials with two plant varieties, Brassica juncea and Lolium multiflorum, and tested four types of biochar to observe changes in ARGs and the microbiome in various plant and soil compartments. This research is particularly significant as it addresses the gap in understanding the effects of biochar on ARGs at the field scale. The findings revealed that biochar significantly altered the distribution of ARGs in soil and plants. Notably, there was a reduction of 1.2-2.2 orders of magnitude in the quantity of ARGs in root and leaf endophytes following biochar addition. Endophytes are microorganisms that live inside plant tissues without causing harm, and their reduction in ARGs points to a potential decrease in the transmission of resistance from soil to plants. However, no significant changes were observed in ARGs in soil and rhizosphere samples, indicating that biochar's impact might be more pronounced within the plant rather than the soil environment. To understand the mechanisms behind these changes, the study employed Procrustes and network analyses, which revealed significant correlations between microbial communities and mobile genetic elements with ARGs. Mobile genetic elements are segments of DNA that can move between different organisms, often carrying resistance genes, thereby facilitating the spread of ARGs. The analyses indicated that bacterial communities play a dominant role in shaping the ARG profile, contributing to 43% of the observed variation in ARGs. These findings suggest that while biochar amendment alone may not fully alleviate ARGs in soil, it has a significant beneficial impact on food safety and human health by effectively reducing ARGs in plant endophytes. This reduction is crucial because it limits the potential for ARGs to enter the food chain, thereby reducing the risk of transmission to humans. The study's results align with previous research indicating the critical role of interconnected habitats in the spread of antibiotic resistance[2]. For example, earlier studies have shown that antibiotic consumption in animals is linked to resistance in human pathogens and vice versa[3]. This bidirectional relationship underscores the importance of a holistic approach to managing antibiotic resistance, considering all interconnected domains. Furthermore, historical evidence suggests that antibiotic resistance can emerge in natural environments independent of human antibiotic use. For instance, methicillin-resistant Staphylococcus aureus (MRSA) was found in European hedgehogs before the clinical use of antibiotics, driven by natural selective pressures[4]. This historical context reinforces the need for comprehensive strategies that address environmental reservoirs of resistance. In conclusion, the study by Zhejiang University provides valuable insights into the potential of biochar to mitigate ARGs in agricultural settings, particularly within plant endophytes. By reducing ARGs in plants, biochar can contribute to safer food production and lower the risk of antibiotic resistance transmission to humans. However, the study also highlights that biochar alone may not be sufficient to address ARGs in soil, pointing to the need for integrated approaches that consider the complex interplay between human, animal, and environmental health.

AgricultureEnvironmentBiotech

References

Main Study

1) Evaluating the impact of biochar amendment on antibiotic resistance genes and microbiome dynamics in soil, rhizosphere, and endosphere at field scale.

Published 5th August, 2024

https://doi.org/10.1016/j.jhazmat.2024.135440

Related Studies

2) Defining and combating antibiotic resistance from One Health and Global Health perspectives.

https://doi.org/10.1038/s41564-019-0503-9

3) Global antimicrobial-resistance drivers: an ecological country-level study at the human-animal interface.

https://doi.org/10.1016/S2542-5196(23)00026-8

4) Emergence of methicillin resistance predates the clinical use of antibiotics.

https://doi.org/10.1038/s41586-021-04265-w


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