Localizing gene regulation reveals a staggered wood decay mechanism for the brown rot fungus Postia placenta

Jiwei Zhang, Gerald N. Presley, Kenneth E. Hammel, Jae San Ryu, Jon R. Menke, Melania Figueroa, Dehong Hu, Galya Orr, Jonathan S. Schilling

Research output: Contribution to journalArticlepeer-review

135 Scopus citations


Wood-degrading brown rot fungi are essential recyclers of plant biomass in forest ecosystems. Their efficient cellulolytic systems, which have potential biotechnological applications, apparently depend on a combination of two mechanisms: lignocellulose oxidation (LOX) by reactive oxygen species (ROS) and polysaccharide hydrolysis by a limited set of glycoside hydrolases (GHs). Given that ROS are strongly oxidizing and nonselective, these two steps are likely segregated. A common hypothesis has been that brown rot fungi use a concentration gradient of chelated metal ions to confine ROS generation inside wood cell walls before enzymes can infiltrate. We examined an alternative: that LOX components involved in ROS production are differentially expressed by brown rot fungi ahead of GH components. We used spatial mapping to resolve a temporal sequence in Postia placenta, sectioning thin wood wafers colonized directionally. Among sections, we measured gene expression by whole-transcriptome shotgun sequencing (RNA-seq) and assayed relevant enzyme activities. We found a marked pattern of LOX up-regulation in a narrow (5-mm, 48-h) zone at the hyphal front, which included many genes likely involved in ROS generation. Up-regulation of GH5 endoglucanases and many other GHs clearly occurred later, behind the hyphal front, with the notable exceptions of two likely expansins and a GH28 pectinase. Our results support a staggered mechanism for brown rot that is controlled by differential expression rather than microenvironmental gradients. This mechanism likely results in an oxidative pretreatment of lignocellulose, possibly facilitated by expansin- and pectinase-assisted cell wall swelling, before cellulases and hemicellulases are deployed for polysaccharide depolymerization.

Original languageEnglish (US)
Pages (from-to)10968-10973
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number39
StatePublished - Sep 27 2016

Bibliographical note

Funding Information:
This work was supported by the US Department of Energy Office of Science [Early Career Grant DE-SC0004012 from the Office of Biological and Ecological Research (BER) to J.S.S.; BER Grant DE-SC0012742 to J.S.S., K.E.H., M.F., and J.Z.]. Confocal microscopy was funded by User Facility Grant 48607 at the Environmental Molecular Sciences Laboratory of Pacific Northwest National Laboratory (to J.S.S., J.Z., and G.N.P.).


  • Bioconversion
  • Biodegradation
  • Cellulase
  • Decomposition
  • Lignocellulose


Dive into the research topics of 'Localizing gene regulation reveals a staggered wood decay mechanism for the brown rot fungus Postia placenta'. Together they form a unique fingerprint.

Cite this