Phylogenetic composition and properties of bacteria coexisting with the fungus Hypholoma fasciculare in decaying wood

White-rot fungi are major degraders of woody materials in terrestrial environments because of their ability to decompose lignin. However, little is known on the possible associations of white-rot fungi with other microorganisms during wood decay. We investigated the numbers, community composition and functional traits of bacteria present in natural wood samples under advanced decay by the white-rot basidiomycete Hypholoma fasciculare. The wood samples contained high numbers of cultivable bacteria (0.2-8 X 10(9) colony forming units (CFU) per g of dry wood). Most cultivable bacteria belonged to Proteobacteria and Acidobacteria (75% and 23% of sequences, respectively). The same phyla were also found to be dominant (59% and 23%, respectively) using a non-culturable quantification technique, namely, direct cloning and sequencing of 16sRNA genes extracted from wood. Bacteria that could be subcultured consisted of acid-tolerant strains that seemed to rely on substrates released by lignocellulolytic enzyme activities of the fungus. There were no indications for antagonism (antibiosis) of the bacteria against the fungus. The ISME Journal (2009) 3, 1218-1221; doi:10.1038/ismej.2009.64; published online 11 June 2009