Sewage Sludge Increases Antibiotic Resistance Genes in Tomato Plants

Jenn Hoskins
11th June, 2024

Sewage Sludge Increases Antibiotic Resistance Genes in Tomato Plants

Image Source: Natural Science News, 2024

Key Findings

  • The study by the Chinese Academy of Sciences examined the xylem microbiome of tomatoes treated with sewage sludge
  • Xylem microbes are less diverse but more metabolically active than those in the soil
  • The xylem contains significantly higher levels of antibiotic resistance genes (ARGs) compared to the soil, especially after sewage sludge treatment
Antibiotic resistance is a growing global health crisis, exacerbated by the widespread use of antibiotics in humans and animals[2][3]. While much attention has focused on antibiotic resistance in clinical settings, recent research has revealed that plants, particularly their xylem, can also serve as reservoirs for antibiotic resistance genes (ARGs). The xylem is a vascular tissue in plants responsible for the upward transport of water and nutrients from the roots to the leaves and fruits. Understanding the microbiome of the xylem and its associated risks, such as antibiotic resistance, is crucial for food safety and crop management. A recent study conducted by the Chinese Academy of Sciences[1] investigated the xylem microbiome of tomatoes and its antibiotic resistance profile following treatment with sewage sludge. The researchers found that the xylem microbiome primarily originates from the soil but exhibits reduced diversity compared to the soil microbiome. This finding aligns with earlier research showing that the xylem selectively recruits certain microbes, often resulting in a less diverse but more functionally specialized community[4]. Using advanced techniques such as single-cell Raman spectroscopy coupled with D2O labeling, the study revealed that xylem microbes exhibit significantly higher metabolic activity compared to those in the rhizosphere soil. Specifically, 87% of xylem microbes were found to be active, in contrast to just 36% in the soil. This high metabolic activity could be due to the unique environment of the xylem, which, despite being nutrient-scarce and in contact predominantly with dead cells, seems to support a thriving microbial community[5]. One of the most concerning findings of this study is that the xylem serves as a reservoir for ARGs, with their abundance being 2.4-6.9 times higher than in rhizosphere soil. The addition of sewage sludge further increased the abundance of ARGs in the xylem, as well as their mobility and host pathogenicity. This is particularly alarming given the global issue of antibiotic resistance and its implications for public health[2][3]. The study's findings highlight the need for better management of the resistome in crops to improve food safety. The resistome refers to the collection of all ARGs in a particular environment. By understanding how ARGs are distributed and maintained in different plant tissues, strategies can be developed to mitigate the spread of antibiotic resistance from plants to humans. In summary, the xylem represents a distinct ecological niche for microbes and serves as a significant reservoir for ARGs. The high metabolic activity of xylem microbes and the increased abundance of ARGs following sewage sludge treatment underscore the potential risks associated with agricultural practices. These findings provide a foundation for future research aimed at managing antibiotic resistance in crops, thereby contributing to global efforts to combat this pressing health issue.

AgricultureGeneticsPlant Science

References

Main Study

1) Sewage Sludge Promotes the Accumulation of Antibiotic Resistance Genes in Tomato Xylem.

Published 10th June, 2024

https://doi.org/10.1021/acs.est.4c02497

Related Studies

2) Review of antibiotic resistance in China and its environment.

https://doi.org/10.1016/j.envint.2017.10.016

3) Antibiotic resistance-the need for global solutions.

https://doi.org/10.1016/S1473-3099(13)70318-9

4) A highly conserved core bacterial microbiota with nitrogen-fixation capacity inhabits the xylem sap in maize plants.

https://doi.org/10.1038/s41467-022-31113-w

5) Pathogen Adaptation to the Xylem Environment.

https://doi.org/10.1146/annurev-phyto-021021-041716


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