Copper in Wood Preservatives Delayed Wood Decomposition and Shifted Soil Fungal but Not Bacterial Community Composition

Abstract

Copper-based fungicides are routinely used for wood and plant protection, which can lead to an enrichment of copper-tolerant microbial communities in soil. To investigate the effect of such wood preservatives on the soil fungal and bacterial community compositions, five different vineyard and fruit-growing soil environments were evaluated using incubation studies over time. Pine sapwood specimens were impregnated with either water or different biocide treatment solutions containing a mixture of copper, triazoles, and quaternary ammonium compounds (CuTriQAC), a mixture of triazoles and quaternary ammonium compounds (TriQAC), or copper alone (Cu). Specimens were incubated in soil from each sample site for 8, 16, 24, and 32 weeks. The effects of preservative treatment on the modulus of elasticity (MOE) of the wood specimens and on the soil fungal as well as bacterial community composition at the soil-wood interface were assessed by quantitative PCR and amplicon sequencing of the fungal internal transcribed spacer (ITS) region and bacterial 16S rRNA gene. Specimens impregnated with CuTriQAC and Cu showed decreased MOE and reduced fungal and bacterial copy numbers over time compared to those impregnated with water and TriQAC. Fungal but not bacterial community composition was significantly affected by wood preservative treatment. The relative abundance of members of the family Trichocomaceae compared to other genera increased in the presence of the Cu and CuTriQAC treatments at three sites, suggesting these to be Cu-tolerant fungi. In conclusion, the copper-containing treatments resulted in marginally increased MOE, lowered microbial gene copy numbers compared to those in the TriQAC and water treatments, and thus enhanced wood protection against soil microbial wood degradation.IMPORTANCECopper-containing rather than TRIQAC formulations are efficient wood preservatives irrespective of the origin and composition of the soil microbial communities. However, some fungi appear to be naturally insensitive to copper and should be the focus of future wood preservative formulations to facilitate the life span of wooden construction in contact with soil while also minimizing the overall environmental impact.

Ganoderma lucidum cultivation affect microbial community structure of soil, wood segments and tree roots

“…The results in our study show consistency with these findings. However, wood preservatives with copper can delay wood breaking down and altered fungi but not bacteria composition of soil 49 . More studies are needed in the future.…”

Biocidal Potential of Plants Extracts Against Wood-Degrading Microbes and Their In-Vitro Application on Wood: As Promising Wood Natural Preservatives

“…As natural products are inexpensive, thus their use for veneer adhesives, lamination of veneers and polishing of crude wood can save wood industry expenditures for importing wood preservative chemicals and crude wood preservative materials. It has been reported that copper in wood preservatives does not inhibit bacterial growth on wood; it only inhibits fungal growth (22). In fact commonly wood preservatives are antifungal they do not have bactericidal potential but bacteria also degrade wood by consuming lignin.…”

“…Bacteria are mostly independent of oxygen thus they intensively compete with fungi in wood degradation (20,21). Mostly wood preservatives used now days are copper containing in origin, they are effective against fungal attack however bacterial colonies are resistant to copper containing wood preservatives (22). Chemicals like creosote, chromatid copper arsenate (CCA) and pentachlorophenol etc.…”

Soil Application of a Formulated Biocontrol Rhizobacterium, Pseudomonas chlororaphis PCL1606, Induces Soil Suppressiveness by Impacting Specific Microbial Communities

“…These impacts on eukaryotic organisms also resulted in a significant difference in the Shannon diversity index for the eukaryotic community, but no differences were observed when analyzing the Chao richness index. The dominant presence of R. necatrix in these soils resulted in white root rot disease, which can be considered conducive for this fungus because it shaped the surrounding environment, promoting the appearance of different fungi, mainly saprobes with aggressive colonization strategies and related to the degradation of wood and organic matter (Lasota et al, 2019). In those samples, the relative abundance of Xylariaceae and especially the species R. necatrix was almost the same in both control soil and rhizosphere samples, with average values above 12%.…”