Heterogeneity of the white truffle Tuber magnatum in a limited geographic area of Central-Southern Italy

Molise region (Central-Southern Italy) is one of the Italian richest areas of truffles and contributes significantly to the national production of the precious Tuber magnatum. Nevertheless, Molise truffle has received little scientific attention. Accordingly, in the present study, two T. magnatum populations collected in two different sites of Molise region were characterised from a morphological, genetic and microbiological point of view. A considerable variability between and within the two analysed groups emerged, suggesting an interesting heterogeneity of Molise white truffle populations. Ascocarps of the two groups significantly differed in size and maturation degree, although no linear correlation between weight and maturity was found. Genetic investigations focused on the Sequence-Characterised Amplified Region SCAR A21-inf. Three haplotypes, randomly distributed within the two truffle groups regardless of their collection sites, were detected. The 16S rRNA gene amplicon high-throughput sequencing provided an overview of the composition of the ascocarp-associated bacterial communities. A predominance of alpha-Proteobacteria was observed, with Bradyrhizobium among the main genera. However, some truffles showed unusual microbial profiles, with Pedobacter, Polaromonas and other bacterial genera as dominant taxa.

Automated summary

The Molise region in Italy is one of the richest areas for truffles and contributes significantly to national production of the valuable Tuber magnatum. A study on two populations of T. magnatum from Molise region revealed significant variability within and between the populations, with three haplotypes identified regardless of collection site. High-throughput sequencing of 16S rRNA gene amplicons showed a predominance of alpha-Proteobacteria in truffle-associated bacterial communities, with some truffles also having unusual microbial profiles dominated by other bacterial genera like Pedobacter and Polaromonas.