Fungal Ecology: Principles and Mechanisms of Colonization and Competition by Saprotrophic Fungi

Abstract

Decomposer fungi continually deplete the organic resources they inhabit, so successful colonization of new resources is a crucial part of their ecology. Colonization success can be split into (i) the ability to arrive at, gain entry into, and establish within a resource and (ii) the ability to persist within the resource until reproduction and dissemination. Fungi vary in their life history strategies, the three main drivers of which are stress (S-selected), disturbance (ruderal, or R-selected), and incidence of competitors (C-selected); however, fungi often have combinations of characteristics from different strategies. Arrival at a new resource may occur as spores or mycelium, with successful entry and establishment (primary resource capture) within the resource largely dependent on the enzymatic ability of the fungus. The communities that develop in a newly available resource depend on environmental conditions and, in particular, the levels of abiotic stress present (e.g., high temperature, low water availability). Community change occurs when these initial colonizers are replaced by species that are either more combative (secondary resource capture) or better able to tolerate conditions within the resource, either through changing abiotic conditions or due to modification of the resource by the initial colonizers. Competition for territory may involve highly specialized species-specific interactions such as mycoparasitism or may be more general; in both cases combat involves changes in morphology, metabolism, and reactive oxygen species production, and outcomes of these interactions can be altered under different environmental conditions. In summary, community development is not a simple ordered sequence, but a complex ever-changing mosaic.

Coupling Secretomics with Enzyme Activities To Compare the Temporal Processes of Wood Metabolism among White and Brown Rot Fungi

“…Variation in oxidoreductases between S. hirsutum and T. versicolor could be one of the determinants of their ecological signatures. Both fungi are early secondary wood colonizers (34,35), but precolonization of beech wood with either fungus produces disparate fungal successional patterns (4). This effect has been attributed to the production of biocidal secondary metabolites by S. hirsutum (36), but in light of this study, variations in decay mechanism and decay residue chemistry may also determine successor communities.…”

Response of Soil Fungal Community to Drought-Resistant Ea-DREB2B Transgenic Sugarcane

“…Notably, TC, TN, and the C:N ratio were the most important factors explaining fungal community structure (Figure 3B), indicating that changes in fungal composition are caused by the effects of fungi altering the physiochemical environment. Fungal community colonization depends on environmental conditions when the resource becomes available for colonization; that is, when the habitat is altered, most fungal communities are usually replaced by other species that are more combative or better able to tolerate conditions within the resource by virtue of certain modifications in their structure or physiology (Boddy and Hiscox, 2017).…”

Functional Genomics, Transcriptomics, and Proteomics Reveal Distinct Combat Strategies Between Lineages of Wood-Degrading Fungi With Redundant Wood Decay Mechanisms

“…One component of competitor response is the expression of fungal cell wall-degrading enzymes. Fungal cell walls, composed primarily of chitin and branched beta glucans, can serve as a source of nutrients for competing fungi as the "losing" competitor's territory is overtaken (Boddy and Hiscox, 2016). Cell wall beta-glucans and chitin are degraded by extracellular glycoside hydrolases (GHs) belonging to several GH families including GH 16 β-glucanases, GH 18 chitinases, and GH 20 β-N-acetyl-glucosaminidases (Martin et al, 2007;Langner and Gohre, 2016).…”