Differences in the activities of eight enzymes from ten soil fungi and their possible influences on the surface structure, functional groups, and element composition of soil colloids

PLoS One. 2014 Nov 14;9(11):e111740. doi: 10.1371/journal.pone.0111740. eCollection 2014.

Abstract

How soil fungi function in soil carbon and nutrient cycling is not well understood by using fungal enzymatic differences and their interactions with soil colloids. Eight extracellular enzymes, EEAs (chitinase, carboxymethyl cellulase, β-glucosidase, protease, acid phosphatase, polyphenol oxidase, laccase, and guaiacol oxidase) secreted by ten fungi were compared, and then the fungi that showed low and high enzymatic activity were co-cultured with soil colloids for the purpose of finding fungi-soil interactions. Some fungi (Gomphidius rutilus, Russula integra, Pholiota adiposa, and Geastrum mammosum) secreted 3-4 enzymes with weak activities, while others (Cyathus striatus, Suillus granulate, Phallus impudicus, Collybia dryophila, Agaricus sylvicola, and Lactarius deliciosus) could secret over 5 enzymes with high activities. The differences in these fungi contributed to the alterations of functional groups (stretching bands of O-H, N-H, C-H, C = O, COO- decreased by 11-60%, while P = O, C-O stretching, O-H bending and Si-O-Si stretching increased 9-22%), surface appearance (disappearance of adhesive organic materials), and elemental compositions (11-49% decreases in C1s) in soil colloids. Moreover, more evident changes were generally in high enzymatic fungi (C. striatus) compared with low enzymatic fungi (G. rutilus). Our findings indicate that inter-fungi differences in EEA types and activities might be responsible for physical and chemical changes in soil colloids (the most active component of soil matrix), highlighting the important roles of soil fungi in soil nutrient cycling and functional maintenance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cellulose / metabolism
  • Chitin / metabolism
  • Coculture Techniques
  • Colloids / chemistry*
  • Elements*
  • Fungal Proteins / metabolism
  • Fungi / enzymology*
  • Fungi / ultrastructure
  • Lignin / metabolism
  • Phosphorus / metabolism
  • Soil / chemistry*
  • Soil Microbiology*
  • Spectrometry, X-Ray Emission
  • Spectrophotometry, Infrared
  • Surface Properties

Substances

  • Colloids
  • Elements
  • Fungal Proteins
  • Soil
  • Chitin
  • Phosphorus
  • Cellulose
  • Lignin

Grants and funding

This study was supported financially by the China's Ministry of Science and Technology (2011CB403205), Fundamental Research Funds for the Central Universities (2572014EA01), China's National Foundation of Natural Sciences (31170575, 41373075). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.