Saprotrophic basidiomycete mycelia and their interspecific interactions affect the spatial distribution of extracellular enzymes in soil

Abstract

Saprotrophic cord-forming basidiomycetes are important decomposers of lignocellulosic substrates in soil. The production of extracellular hydrolytic enzymes was studied during the growth of two saprotrophic basidiomycetes, Hypholoma fasciculare and Phanerochaete velutina, across the surface of nonsterile soil microcosms, along with the effects of these basidiomycetes on fungi and bacteria within the soil. Higher activities of α-glucosidase, β-glucosidase, cellobiohydrolase, β-xylosidase, phosphomonoesterase and phosphodiesterase, but not of arylsulphatase, were recorded beneath the mycelia. Despite the fact that H. fasciculare, with exploitative hyphal growth, produced much denser hyphal cover on the soil surface than P. velutina, with explorative growth, both fungi produced similar amounts of extracellular enzymes. In the areas where the mycelia of H. fasciculare and P. velutina interacted, the activities of N-acetylglucosaminidase, α-glucosidase and phosphomonoesterase, the enzymes potentially involved in hyphal cell wall damage, and the utilization of compounds released from damaged hyphae of interacting fungi, were particularly increased. No significant differences in fungal biomass were observed between basidiomycete-colonized and noncolonized soil, but bacterial biomass was reduced in soil with H. fasciculare. The increases in the activities of β-xylosidase, β-glucosidase, phosphomonoesterase and cellobiohydrolase with increasing fungal:bacterial biomass ratio indicate the positive effects of fungal enzymes on nutrient release and bacterial abundance, which is reflected in the positive correlation of bacterial and fungal biomass content.

Patterns of laccase and peroxidases in coarse woody debris of Fagus sylvatica, Picea abies and Pinus sylvestris and their relation to different wood parameters

“…Recently, van der Wal et al (2015) demonstrated that the fungal community in old Q. robur stumps is similar to a randomly assembled community. Moreover, the status of development of each fungus and the status of interaction between the fungi will be relevant, too, since: (1) each fungus accomplishes an individual set and temporal pattern of extracellular oxidoreductase activities (Liers et al 2011), (2) these activities are higher when a fungus is capturing fresh unoccupied wood (Hahn et al 2013;Větrovský et al 2010), (3) during interaction of several fungal species, activities of Lacc or MnP can increase (Baldrian 2004;Hiscox et al 2010;Š najdr et al 2011), and (4) competition between fungi can hamper wood degradation (Fukasawa et al 2009b). This complex interplay of fungal species may be the reason for the observed extreme variability (Table 3) and cannot be explained by solely analyzing the fungal community.…”

Linking molecular deadwood-inhabiting fungal diversity and community dynamics to ecosystem functions and processes in Central European forests

“…The co-occurrence of these fungi in deadwood suggests that there is some functional redundancy within the studied WIF communities. Several authors have reported increased Lac and MnP activities due to two-speciesinteractions (Baldrian 2004;Freitag and Morrell 1992;Snajdr et al 2011;White and Boddy 1992). Chi et al (2007) found that some combinations of two fungi can accelerate the decay of wood due to increases in MnP production relative to that observed in equivalent cases featuring only a single fungal species.…”

A PCR-based method to quantify fungal growth during pretreatment of lignocellulosic biomass

“…The small amount of material used for genomic DNA extraction (100 mg) and heterogeneity in fungus distribution in the substrate could explain the observed disparity, as previously observed in soil samples (Feinstein et al, 2009, Snajdr et al, 2011. Despite this limitation, the qPCR-based method described here allows fungal growth assessment and selection of the most appropriate fungal strains in specific SSF/reactor conditions.…”

“…Recently, several studies have shown the reliability of this method for monitoring and quantifying ochratoxin A producing strains in several food matrices (Rodriguez et al, 2011) or for quantifying fungus biomass in soil (Feinstein et al, 2009;Snajdr et al, 2011). We developed a qPCR-based method to quantify fungal biomass during SSF.…”