Bacteria associated to fruit bodies of the ectomycorrhyzal fungus Tuber borchii Vittad

A microbial population was isolated from young sporocarps of Tuber borchii Vittad. to study its possible role in ascus opening. The bacteria in the sporocarps had a mean value of 106 CFU/g and were generally found in quantities higher than that found in the bulk soil (103). In the sporocarps examined the predominant bacteria were Pseudomonas fluorescens (30% of the total population) and spore-forming, gram-positive, bacteria (15% of total). These bacterial species were tested to evaluate their capacity to degrade cellulose and chitin, the most important components of the hyphal walls. Ultrastructural examination of the tested sporocarps revealed the presence of bacteria in the interhyphal space, a portion of which were embedded in the ascus wall. It is suggested that the presence of Pseudomonas strains and Bacillaceae in T. borchii Vittad. sporocarps could be related to their chitinolytic and cellulolytic activities, which could in turn be involved in ascus opening and, perhaps, in spore germination.