Extracellular Enzymatic Activities of Oceanic Pelagic Fungal Strains and the Influence of Temperature

Author(s)
Katherine Salazar Alekseyeva, Gerhard J. Herndl, Federico Baltar
Abstract

Although terrestrial and aquatic fungi are well-known decomposers of organic matter, the role of marine fungi remains largely unknown. Recent studies based on omics suggest that marine fungi potentially play a major role in elemental cycles. However, there is very limited information on the diversity of extracellular enzymatic activities performed by pelagic fungi in the ocean and how these might be affected by community composition and/or critical environmental parameters such as temperature. In order to obtain information on the potential metabolic activity of marine fungi, extracellular enzymatic activities (EEA) were investigated. Five marine fungal species belonging to the most abundant pelagic phyla (Ascomycota and Basidiomycota) were grown at 5 degrees C and 20 degrees C, and fluorogenic enzymatic assays were performed using six substrate analogues for the hydrolysis of carbohydrates (beta-glucosidase, beta-xylosidase, and N-acetyl-beta-D-glucosaminidase), amino acids (leucine aminopeptidase), and of organic phosphorus (alkaline phosphatase) and sulfur compounds (sulfatase). Remarkably, all fungal strains were capable of hydrolyzing all the offered substrates. However, the hydrolysis rate (V-max) and half-saturation constant (K-m) varied among the fungal strains depending on the enzyme type. Temperature had a strong impact on the EEAs, resulting in Q(10) values of up to 6.1 and was species and substrate dependent. The observed impact of temperature on fungal EEA suggests that warming of the global ocean might alter the contribution of pelagic fungi in marine biogeochemical cycles.

Organisation(s)
Functional and Evolutionary Ecology
Journal
Journal of Fungi
Volume
8
No. of pages
17
ISSN
2309-608X
DOI
https://doi.org/10.3390/jof8060571
Publication date
05-2022
Peer reviewed
Yes
Austrian Fields of Science 2012
106021 Marine biology
Keywords
ASJC Scopus subject areas
Microbiology (medical), Ecology, Evolution, Behavior and Systematics, Plant Science
Sustainable Development Goals
SDG 14 - Life Below Water
Portal url
https://ucris.univie.ac.at/portal/en/publications/extracellular-enzymatic-activities-of-oceanic-pelagic-fungal-strains-and-the-influence-of-temperature(fc1bf48b-1fe7-423d-9e23-43a9e1f8a901).html