Zearalenone lactonohydrolase activity in Hypocreales and its evolutionary relationships within the epoxide hydrolase subset of a/b-hydrolases

Author: mycolabadmin
2014-04-03
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Summary

This research discovered a new enzyme in the fungus Trichoderma aggressivum that can break down a dangerous toxin called zearalenone, which commonly contaminates crops and poses health risks to animals and humans. The enzyme works by breaking open the toxin’s molecular structure, making it harmless. This discovery has important implications for food safety and agricultural practices. Impacts on everyday life: – Could lead to better methods for detoxifying contaminated grain and animal feed – May help reduce economic losses in livestock farming due to mycotoxin contamination – Potential development of natural biocontrol agents for crop protection – Could improve food safety by providing new ways to detect and eliminate toxins – May lead to development of environmentally friendly alternatives to chemical treatments

Background

Zearalenone is a mycotoxin produced by several species of Fusarium genus, most notably F. graminearum and F. culmorum. This resorcylic acid lactone is one of the most important toxins causing serious animal and human diseases. For over two decades it has been known that the mycoparasitic fungus Clonostachys rosea can detoxify zearalenone, however no such attributes have been described within the Trichoderma genus.

Objective

To screen for the presence of zearalenone lactonohydrolase homologs in isolates of Clonostachys and Trichoderma genera and verify their biotransformation ability potential. Additionally, to assess progression of the detoxification process and search for evolutionary origins of zearalenone lactonohydrolase activity in model fungal and bacterial genomes.

Results

The study identified functional zearalenone lactonohydrolase in Trichoderma aggressivum for the first time, along with confirming activity in Clonostachys rosea and Clonostachys catenulatum isolates. The enzyme showed different expression patterns across species, with T. aggressivum exhibiting induced expression while C. rosea and C. catenulatum showed constitutive or gradually increasing expression. Homology models revealed conservation of key catalytic residues and structural features across species. Phylogenetic analysis indicated the enzyme likely evolved before the split between Leotiomycetes and Sordariomycetes.

Conclusion

This research demonstrates the first finding of functional zearalenone lactonohydrolase in mycoparasitic Trichoderma aggressivum. The supporting evidence includes chemical analyses, gene expression patterns, homology models showing conservation of key structural features, and marked reduction of zearalenone content in cultured samples. The findings also reveal divergent strategies of zearalenone biotransformation ability present in several members of Hypocreales order.

Published in:BMC Microbiology,
Study Type:Laboratory Research,
Source: 10.1186/1471-2180-14-82