The Science
Soil fungi secrete a wide range of enzymes that not only play an important role in biogeochemistry, but also biofuel production and bioremediation of metal-contaminated soils and water. A recent study shed new light on the 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 our understanding of the role of fungi 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 tough 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 Mn(II)-oxidizing capacity of certain fungal species can be harnessed to remove toxic metals from contaminated soils and water, as well as break down lignocellulosic plant material for biofuel production. Yet few studies have characterized enzymes secreted by diverse Mn(II)-oxidizing fungi that are commonly found in the environment. To address this gap in knowledge, a team of researchers recently characterized and compared enzymes secreted by four Mn(II)-oxidizing Ascomycetes species recently isolated from coal mine drainage treatment systems and a freshwater lake contaminated with high concentrations of metals using liquid chromatography-tandem mass spectrometry (LC-MS/MS), genomic, and bioinformatic analyses. These four species are associated with varied environments and are 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 EMSL, the Environmental Molecular Sciences Laboratory, an Office of Science user facility. This analysis revealed 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 our understanding of the role of Ascomycetes in biogeochemistry and climate dynamics, and reveal lignocellulose-degrading enzymes that could potentially be engineered for renewable energy production or bioremediation of metal-contaminated waters. This study represents collaboration among scientists from Harvard University, EMSL, Pacific Northwest National Laboratory, the Smithsonian Institution, the Department of Energy (DOE) Joint Genome Institute, Centre National de la Recherche Scientifique and Aix-Marseille Université, King Abdulaziz University, the University of Minnesota, and Woods Hole Oceanographic Institution.
PI Contact
Colleen Hansel, Woods Hole Oceanographic Institution, chansel@whoi.edu
Funding
This work was supported by DOE’s Office of Science (Office of Biological and Environmental Research), including support of EMSL and the DOE Joint Genome Institute, Office of Science User Facilities, and Woods Hole Oceanographic Institution.
Publication
C.A. Zeiner, S.O. Purvine, E.M. Zink, L. Paša-Tolić, D.L. Chaput, S. Haridas, S. Wu, K. LaButti, I.V. Grigoriev, B. Henrissat, C.M. Santelli, and C.M. Hansel, “Comparative analysis of secretome profiles of manganese(ii)-oxidizing Ascomycete fungi.” PLOS ONE (2016). doi:10.1371/journal.pone.0157844