Genetic analysis of cellobiohydrolase I (cbhI) gene sequences and production of other wood degradation enzymes in tropical aquatic fungal communities

Boyce, Matthew

Permalink

https://hdl.handle.net/2142/77760 Copy

Description

Title

Genetic analysis of cellobiohydrolase I (cbhI) gene sequences and production of other wood degradation enzymes in tropical aquatic fungal communities

Author(s)

Boyce, Matthew

Contributor(s)

Dalling, James

Issue Date

2015-05

Keyword(s)

• Integrative Biology
• cellobiohydrolase
• cellulose
• aquatic fungi
• nutrient cycling
• wood decay

Abstract

Dead plant biomass represents a major source of energy supporting aquatic food webs. Fungal communities play an important role in making this energy available through the breakdown of complex plant polymers via hydrolytic enzymes. The objectives of this study were to determine (1) whether aquatic fungi possess cbhI genes for the production of cellobiohydrolase, a major class of cellulolytic enzymes present in terrestrial fungi, and (2) to examine the effects of salinity on the production of wood degrading enzymes in cultures of aquatic fungi grown in vitro. Colonies of seven ascomycete taxa were grown from single spore isolates obtained from wood collected along a freshwater-marine salinity gradient in rivers on Coiba Island, Panama. Primers for cbhI were used to successfully amplify DNA from 4 out of 7 fungal cultures without the need for cloning, suggesting that cbhI is a single-copy gene in Ascomycetes. Four aquatic Ascomycetes, cultured from wood from the same sites, were screened for their ability to produce degradative enzymes on solid media across a salinity gradient. Enzymes tested were: endoglucanase, -glucosidase, and xylanase. Results suggested that salinity affects growth and enzyme production in a species-specific manner. Freshwater taxa grew significantly faster and produced wood degrading enzymes more consistently in less saline environments. In contrast, marine taxa were observed to grow across a range of salinity levels, but had the highest level of enzyme production in more saline environments. This study shows that aquatic ascomycete fungi share at least some of the enzymatic capabilities of their terrestrial basidiomycete counterparts, and that salinity effects on enzyme production may be an important control on aquatic fungal species distribution.

Type of Resource

text

Language

en

Permalink

http://hdl.handle.net/2142/77760

Copyright and License Information

Copyright 2015 Matthew Boyce.

Owning Collections