New insight regarding mode of action of brown rot decay of modified wood based on DNA and gene expression studies: a review

Abstract

Modified wood shows resistance against wood deteriorating fungi, but the mechanisms are still not fully understood. The aim of this paper was to summarise the molecular studies performed on modified wood with regard to brown rot decay fungi. The DNA data showed that fungi are present inside the laboratory wood test samples already after two weeks of inoculation. Generally the fungal DNA content reflects mass loss and wood moisture content. The oxidative gene expression seems to be higher in modified wood than in untreated wood and it tend to increase during incubation. Based on the gene expression data we suggest that the hypothesis of lack of substrate recognition by the fungus should be rejected. In the reviewed studies, total wood moisture content in the samples was generally not low enough to inhibit fungal colonisation. Hence, moisture distribution within the wood should be studied more closely.

Decay Resistance of Acetic, Propionic, and Butyric Anhydrides Modified Rubberwood Against Brown Rot (Coniophora puteana)

“…These SEM images supported the theory that the decaying process was slowed by lower moisture content. In the DNA and genes expression study by Alfredsen et al (2014), brown rot DNA was present inside the modified wood for up to 36 weeks without any mass loss being recorded, which was also consistent with the SEM images. This study strongly suggested that the low moisture content was the mechanism that slowed the decay process in the modified rubberwood.…”

“…As a consequence, CCA-treated wood was banned from use in playgounds to prevent direct contact with skin (Hill 2006). Many wood modification treatments have different decay resistance perfromances and other overall properties ( Li et al 2000;Hill et al 2005;Del Menezzi et al 2008;Kartal et al 2009;Unsal et al 2009). Alternatively, chemical modification offers the best solution to improve the dimensional stability and decay resistance of wood, without altering important mechanical properties, especially the load bearing properties Rowell 2014).…”

Wood modification technologies - a review

“…However, recent research works (Alfredsen et al 2015 have demonstrated that the mechanism of substrate recognition by the fungus should be considered as critical, in combination with the lowered moisture content as distributed within the wood matrix.…”

Initial Rhodonia placenta Gene Expression in Acetylated Wood: Group-Wise Upregulation of Non-Enzymatic Oxidative Wood Degradation Genes Depending on the Treatment Level

“…The ten genes used in this study were chosen because of their assumed importance during the non-enzymatic degradation phase. This selection was based on previous findings [11,13,47,[68][69][70][75][76][77][78][79]. Most importantly, the ten genes included in this paper have never been studied with this sample design before.…”