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Abstract
Copper-tolerant brown-rot decay fungi exploit intricate mechanisms to neutralize the efficacy of copper-containing preservative formulations. The production and accumulation oxalate is the most widely recognized theory regarding the mechanism of copper-tolerance in these fungi. The role of oxalate, however, may be only one part of a series of necessary components required for this complex mechanism. Annotation of the
Fibroporia radiculosa genes involved in copper-tolerance characterized a subset of proteins, three copper-transporting ATPase pumps, which regulate copper concentrations inside the fungal cell by exporting excess copper ions. The goal of this study was to determine the relevance of copper-transporting ATPase pumps in the mechanism of
F. radiculosa copper-tolerance. Southern pine test blocks were pressure-treated with 0.6%, 1.2% and 2.4% ammoniacal copper citrate and subjected to a copper-tolerant strain of
F. radiculosa and a copper-sensitive strain of
Gloeophyllum trabeum in decay tests over a four week period. Untreated Southern pine test blocks subjected to both test fungi served as controls. Expression levels of three copper-transporting ATPase pumps were evaluated each week by qRT-PCR.
F. radiculosa showed up regulation of all three ATPase pumps when exposed to the copper treatments over the course of this study.
G trabeum showed down-regulation of ATPase1 and ATPase2 and no expressions of ATPase3 when exposed to the copper treatments over the course of this study. Up-regulation of the three ATPase pumps can be correlated to the ability of
F. radiculosa to decay copper-treated wood (1% weight loss at week 4). Preliminary results indicate these three ATPase pumps function as an essential component of the complex mechanism of copper-tolerance utilized by
F. radiculosa.
Citation
Ohno, Katie M.; Clausen, C.A.; Green III, F.; Stanosz, G. 2016. The copper-transporting ATPase pump and its potential role in copper-tolerance. In. Proceedings IRG Annual Meeting (ISSN 2000-8953). The International Research Group on Wood Protection; IRG/WP 16-10859, Section 1, Biology. pp, 1-15.
