Abstract:

Truffles are important economic fungi, and bacteria play an important role in their growth and development. We investigated the bacterial community composition inside ascocarps of Tuber indicum. Using the traditional culture method, 532 isolates were obtained from ascocarps. Using the rarefaction curve, the 16S rRNA gene was collected and sequenced from 112 purified isolates to identify 4 genera and 40 species. Isolates of the genera Pseudomonas, Acinetobacter, Streptomyces and Variovorax accounted for 80%, 12.5%, 5% and 2.5% of the number of these sequenced isolates, respectively. On the other hand, 9,862 sequences of the bacterial V1-V3 region of 16S rRNA gene, which represented 220 species, were analyzed via Roche 454 high-throughput sequencing. Species of the phyla Proteobacteria, Bacteroidetes, and Actinobacteria were dominant, accounting for 99.7% of all identified species. Genera Flavobacterium, Agromyces, Microbacterium, Ensifer, and Stenotrophomonas were dominant among the bacteria identified with this alternative method, accounting for 86.3% of the number of total species. It was found that relatively few bacterial species were isolated from ascocarps of T. indicum when analyzed via traditional culture method. The bacterial population associated with ascocarps of T. indicum was augmented when analyzed by Roche 454 high-throughput sequencing, which indicates that this latter method provides more comprehensive results.

Key words: Tuber indicum, acocarps, bacteria, culture, high-throughput sequencing