Truffle ground
ITS-1 versus 1 ITS-2 pyrosequencing: a comparison of fungal populations in truffle ground
Here we compare the two ITS regions, ITS-1 and ITS-2, of the fungal populations occurring in Tuber melanosporum/Quercus pubescens truffle grounds and sampled in two areas, an area devoid of vegetation (“the burnt”, brulé in French) where Tuber melanosporum fruiting bodies are usually collected, and outside. Two amplicon libraries were built, one for inside and the other for outside. A set of 15.788 ITS reads was obtained. After the removal of low quality sequences, 3568 and 3156 sequences were obtained from inside the brulé with the ITS-1 and ITS-2 primers respectively. The sequences obtained from outside the brulé were 4490 with the ITS-1 primers, and 2432 with the ITS-2 primers. Most of the sequences obtained for both ITS fragments could be attributed to fungal organisms. The non-fungal sequences amplified with the ITS-1 primers were 1% inside and 3% outside whereas those amplified with the ITS-2 primers were 6% inside and 11% outside. Although differences are present in the taxa percentages between ITS-1 and ITS-2, both reveal that Ascomycota were the dominant fungal Phylum and that their number decreased moving from the inside to the outside of the brulé, while the number of Basidiomycota incresead.  Taken together, both the short ITS-1 and ITS-2 reads obtained by the high-throughput 454 sequencing provide adequate information for taxon assignment and are suitable to correlate the dynamics of the fungal populations to specific environments.