Bacterial communities associated with wood rot fungi that use distinct decomposition mechanisms

Irshad Ul Haq; Benjamin Hillmann; Molly Moran; Samuel Willard; Dan Knights; Kathryn R Fixen; Jonathan S Schilling

doi:10.1038/s43705-022-00108-5

Bacterial communities associated with wood rot fungi that use distinct decomposition mechanisms

ISME Commun. 2022 Mar 30;2(1):26. doi: 10.1038/s43705-022-00108-5.

Authors

Irshad Ul Haq^{1

2}, Benjamin Hillmann³, Molly Moran¹, Samuel Willard⁴, Dan Knights^{2

3}, Kathryn R Fixen^{1

2}, Jonathan S Schilling^{5

6}

Affiliations

¹ Department of Plant and Microbial Biology, College of Biological Sciences, University of Minnesota, St. Paul, MN, USA.
² Biotechnology Institute, College of Biological Sciences, University of Minnesota, Minneapolis, MN, USA.
³ Department of Computer Science and Engineering, University of Minnesota, Minneapolis, MN, USA.
⁴ Department of Life Sciences, Imperial College London, London, UK.
⁵ Department of Plant and Microbial Biology, College of Biological Sciences, University of Minnesota, St. Paul, MN, USA. schillin@umn.edu.
⁶ Biotechnology Institute, College of Biological Sciences, University of Minnesota, Minneapolis, MN, USA. schillin@umn.edu.

Abstract

Wood decomposer fungi are grouped by how they extract sugars from lignocellulose. Brown rot fungi selectively degrade cellulose and hemicellulose, leaving lignin intact, and white rot fungi degrade all components. Many trees are susceptible to both rot types, giving carbon in Earth's woody biomass, specifically lignin, a flexible fate that is affected not only by the fungal decomposition mechanism but also the associated microbial community. However, little is understood about how rot type may influence the microbial community in decaying wood. In this study, we quantified bacterial communities associated with Fomes fomentarius (white rot) and Fomitopsis betulina (brown rot) found on a shared tree host species, birch (Betula papyrifera). We collected 25 wood samples beneath sporocarps of F. fomentarius (n = 13) and F. betulina (n = 12) on standing dead trees, and coupled microbial DNA sequencing with chemical signatures of rot type (pH and lignin removal). We found that bacterial communities for both fungi were dominated by Proteobacteria, a commonly reported association. However, rot type exerted significant influence on less abundant taxa in ways that align logically with fungal traits. Amplicon sequence variants (ASVs) were enriched in Firmicutes in white-rotted wood, and were enriched in Alphaproteobacteria, Actinobacteria and Acidobacteria in lower pH brown rot. Our results suggest that wood decomposer strategies may exert significant selection effects on bacteria, or vice versa, among less-abundant taxa that have been overlooked when using abundance as the only measure of influence.