Bacteria in decomposing wood and their interactions with wood-decay fungi

Abstract

The fungal community within dead wood has received considerable study, but far less attention has been paid to bacteria in the same habitat. Bacteria have long been known to inhabit decomposing wood, but much remains underexplored about their identity and ecology. Bacteria within the dead wood environment must interact with wood-decay fungi, but again, very little is known about the form this takes; there are indications of both antagonistic and beneficial interactions within this fungal microbiome. Fungi are hypothesised to play an important role in shaping bacterial communities in wood, and conversely, bacteria may affect wood-decay fungi in a variety of ways. This minireview considers what is currently known about bacteria in wood and their interactions with fungi, and proposes possible associations based on examples from other habitats. It aims to identify key knowledge gaps and pressing questions for future research.

Bacterial communities of decaying Norway spruce follow distinct slope exposure and time‐dependent trajectories

“…There is evidence for a close fungal‐bacterial interaction within the deadwood environment as recently reviewed by Johnston and colleagues (). The abundance of fungi, inferred from fungal 18S rRNA gene abundances obtained by real‐time PCR (qPCR; Bardelli et al ., ), was much higher in wood compared with soil samples (mean soil = 9.6e8 copies g dry weight −1 , mean wood = 1.2e11 copies g dry weight −1 , p = 1.9e‐10).…”

“…Due to low nitrogen availability in deadwood it has been hypothesised that wood-inhabiting fungi might benefit from associations with nitrogen-fixing bacteria to meet their nitrogen requirements for vegetative and generative growth (Merrill and Cowling, 1966;Johnston et al, 2016). Hoppe and colleagues (2015) reported that diazotrophic Alphaproteobacteria (Rhizobiales) accounted for up to 25% of the bacterial community in P. abies logs during the intermediate and advanced stages of decay.…”

“…Deadwood provides shelter and nutrition to a wide range of saproxylic organisms and it largely influences the global forest carbon (C) balance acting as a temporal store estimated at 73 Pg C (Pan et al, 2011). Moreover, there exists evidence of complex fungalbacterial interactions, both positive and negative, within the deadwood environment, even though, the identity and ecology of bacterial communities in decaying wood remains underexplored compared with fungi which are supposed to be the main deadwood decomposers (Valášková et al, 2008;Sun et al, 2014;Hoppe et al, 2015;Hervé et al, 2016;Johnston et al, 2016;Kielak et al, 2016;Rinta-Kanto et al, 2016;Tláskal et al, 2017).…”

Bacteria inhabiting deadwood of 13 tree species are heterogeneously distributed between sapwood and heartwood

“…Microbial communities are affected by several environmental factors , but not all wood‐structure components influence these communities. There are several reports stating that dioxygen availability, directly or indirectly depending on water content and pH, and the latter in their own right, are critical factors affecting wood‐inhabiting biota and thus the decomposition rate (Kazemi et al ., ; Cornelissen et al ., ; Johnston et al ., ). These findings have been confirmed by our results.…”

Chemical and microbiological changes in Norway spruce deadwood during the early stage of decomposition as a function of exposure in an alpine setting

“…Evidence also exists of complex fungal-bacterial interactions, both positive and negative, within the deadwood environment as reviewed by Johnston, Boddy, and Weightman (2016), even though the identity and ecology of bacterial communities in decomposing wood remained underexplored compared to fungi. For instance, one assumes that fungi might be able to meet the nitrogen requirements for their vegetative and generative growth through the associations with nitrogen-fixing bacteria.…”