Wood modification by furfuryl alcohol caused delayed decomposition response in Rhodonia (Postia) placenta
Skrede, Inger; Hess, Jaqueline; Solbakken, Monica Hongrø; Fossdal, Carl Gunnar; Hegnar, Olav Aaseth; Alfredsen, Gry
Journal article, Peer reviewed
Published version
Date
2019-07-01Metadata
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Abstract
The aim of this study was to investigate differential expression profiles
of the brown rot fungus Rhodonia placenta (previously Postia placenta) harvested at
several time points when grown on radiata pine (Pinus radiata) and radiata pine
with three different levels of modification by furfuryl alcohol, an environmentally benign
commercial wood protection system. The entire gene expression pattern of a
decay fungus was followed in untreated and modified wood from initial to advanced
stages of decay. The results support the current model of a two-step decay
mechanism, with the expression of genes related to initial oxidative depolymerization,
followed by an accumulation of transcripts of genes related to the hydrolysis of
cell wall polysaccharides. When the wood decay process is finished, the fungus goes
into starvation mode after five weeks when grown on unmodified radiata pine wood.
The pattern of repression of oxidative processes and oxalic acid synthesis found in radiata
pine at later stages of decay is not mirrored for the high-furfurylation treatment.
The high treatment level provided a more unpredictable expression pattern
throughout the incubation period. Furfurylation does not seem to directly influence
the expression of core plant cell wall-hydrolyzing enzymes, as a delayed and prolonged,
but similar, pattern was observed in the radiata pine and the modified experiments.
This indicates that the fungus starts a common decay process in the
modified wood but proceeds at a slower pace as access to the plant cell wall polysaccharides
is restricted. This is further supported by the downregulation of hydrolytic
enzymes for the high treatment level at the last harvest point (mass loss, 14%).
Moreover, the mass loss does not increase during the last weeks. Collectively, this
indicates a potential threshold for lower mass loss for the high-furfurylation treatment.