07/19/2016

Diverse Fungi Secrete Similar Suite of Decomposition Enzymes

Genomic and proteomic analyses reveal diversity in carbon turnover and other degradation processes.

The Science

Soil fungi secrete a wide range of enzymes that play an important role in biogeochemistry as well as in biofuel production and bioremediation of metal-contaminated soils and water. A recent study sheds new light on a suite of enzymes secreted by diverse fungal species commonly found in soil ecosystems worldwide.

The Impact

The findings reveal different fungal species secrete a rich set of enzymes that share similar functions, despite species-specific differences in the amino acid sequences of these enzymes. This information enhances understanding of the role fungi play in biogeochemical processes occurring in soil and could be used to engineer fungal enzymes for biofuel production and bioremediation efforts.

Summary

Fungi secrete a diverse repertoire of enzymes that break down tenacious plant material. These powerful enzymes degrade plant cell wall components such as cellulose and lignin, resulting in the release of carbon dioxide from soils with dead plant material into the atmosphere. As such, fungal enzymes are not only critical drivers of climate dynamics, but they also hold promise for cost-effective development of alternative transportation fuels. Moreover, the manganese [Mn(II)]-oxidizing capacity of certain fungal species can be harnessed to remove toxic metals from contaminated soils and water. Yet few studies have characterized enzymes secreted by diverse Mn(II)-oxidizing fungi that are commonly found in the environment. To address this knowledge gap, a team of researchers recently used liquid chromatography-tandem mass spectrometry (LC-MS/MS), genomic, and bioinformatic analyses to characterize and compare enzymes secreted by four Mn(II)-oxidizing Ascomycetes species. These four species were recently isolated from coal mine drainage treatment systems and a freshwater lake contaminated with high concentrations of metals and are associated with varied environments and common in soil ecosystems worldwide. The researchers performed LC-MS/MS-based comparative proteomics using the Linear Ion Trap Quadrupole Orbitrap Velos mass spectrometer at the Department of Energy’s (DOE) Environmental Molecular Sciences Laboratory (EMSL), a DOE Office of Science user facility. This analysis revealed that fungi secrete a rich yet functionally similar suite of enzymes, despite species-specific differences in the amino acid sequences of these enzymes. These findings enhance understanding of the role Ascomycetes species play in biogeochemistry and climate dynamics and reveal lignocellulose-degrading enzymes that potentially could be engineered for renewable energy production or bioremediation of metal-contaminated waters. This study represents a collaboration among scientists from Harvard University, EMSL, Pacific Northwest National Laboratory, Smithsonian Institution, DOE Joint Genome Institute (JGI), Centre National de la Recherche Scientifique and Aix-Marseille Université, King Abdulaziz University, University of Minnesota, and Woods Hole Oceanographic Institution.

Principal Investigator(s)

Carolyn Zeiner
Harvard University
[email protected]

Funding

This work was supported by DOE’s Office of Science, Office of Biological and Environmental Research, including support of EMSL and JGI, Office of Science user facilities, and Harvard University.

References

Zeiner, C. A., S. O. Purvine, E. M. Zink, L. PaÅ¡a-ToliÄ‡, D. L. Chaput, S. Haridas, S. Wu, K. LaButti, I. V. Grigoriev, B. Henrissat, C. M. Santelli, and C. M. Hansel. 2016. “Comparative Analysis of Secretome Profiles of Manganese(II)-Oxidizing Ascomycete Fungi,” PLOS ONE 11(7), e0157844. [DOI:10.1371/journal.pone.0157844].