Ochratoxin A Degradation and Stress Response Mechanism of Brevundimonas naejangsanensis ML17 Determined by Transcriptomic Analysis

Zitong Zhao ¹, Zehui Niu ¹, Zhihong Liang ^1,2,3

⁰College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.

Foods (basel, Switzerland) +

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December 17, 2024

View abstract on PubMed

Summary

Brevundimonas naejangsanensis ML17 effectively degrades high concentrations of Ochratoxin A (OTA), a harmful mycotoxin. This bacterium enhances its metabolism and antioxidant systems to resist and break down OTA, offering a promising bioremediation strategy.

Area Of Science

Microbiology
Food Safety
Bioremediation

Background

Ochratoxin A (OTA) is a prevalent mycotoxin from Aspergillus and Penicillium species, posing significant risks to human health and food safety.
Previous research indicated Brevundimonas naejangsanensis ML17's capability to degrade OTA at 1 μg/mL.

Purpose Of The Study

To evaluate the degradation efficacy of B. naejangsanensis ML17 on varying concentrations of OTA.
To elucidate the underlying mechanisms by which ML17 degrades OTA.

Main Methods

Bacterial growth assays under different OTA concentrations.
Transcriptomic analysis to identify gene expression changes in response to OTA.
Functional enrichment analysis to understand metabolic pathway alterations.

Main Results

B. naejangsanensis ML17 growth is unaffected by up to 6 μg/mL OTA within 24 hours.
ML17 almost completely degrades 12 μg/mL OTA within 36 hours, converting it to non-toxic OTα and L-phenylalanine.
Transcriptomic analysis revealed upregulation of 275 genes, including those involved in translation, metabolism, oxidative phosphorylation, heat shock proteins, and antioxidant systems (peroxiredoxin, superoxide dismutase, glutaredoxin 3).
The enzyme-coding gene0095, implicated in OTA degradation, was significantly upregulated.

Conclusions

B. naejangsanensis ML17 demonstrates robust degradation capabilities for high OTA concentrations.
The bacterium employs a multi-faceted strategy involving metabolic regulation, enhanced antioxidant defense, and upregulation of specific degradation enzymes to counteract OTA toxicity.
This study provides crucial insights into the molecular mechanisms of OTA biodegradation by ML17, supporting its potential application in food safety and mycotoxin bioremediation.

Keywords:

Brevundimonas naejangsanensis ML17 anti-oxidative stress degradation mechanism detoxifying enzyme ochratoxin A stress response transcriptomic analysis