Tuber spp. biodiversity in one of the southernmost European distribution areas

Abstract

The aims of this paper were to study the genetic diversity within and among 6 Tuber taxa, the phylogenetic relationships and the spatial distribution of truffles from the Basilicata region (southern Italy). Molecular analyses, using the internal transcribed spacer region, microsatellites, minisatellites and random amplified polymorphic loci revealed the highest expected intra-specific heterozygosity (He=0.30) in T. aestivum, followed by that of T. mesentericum (He=0.22). T. borchii (He=0.17), T. magnatum (He=0.16), T. aestivum fo. uncinatum (He=0.12) and T. brumale fo. moschatum (He=0.09) showed a lower average heterozygosity. The whole set of markers were demonstrated to be useful in clearly differentiating Tuber taxa, separating them in two distinct groups and in five sub-clusters, each corresponding to one single taxon. The first cluster (T. borchii, T. magnatum and T. brumale fo. moschatum) was more differentiated than the second one (T. aestivum, T. aestivum fo. uncinatum and T. mesentericum). T. brumale fo. moschatum was the most differentiated Tuber taxon. It was more related to the white truffles (the closely related T. borchii and T. magnatum) than to the remaining related black truffles T. aestivum and T. mesentericum. The amount of Tuber species richness was higher over the western side of Basilicata, in cold Lauretum and in Castanetum phytoclimatic Pavari’s zones. A spatial genetic structure was detected for T. aestivum, as shown by the significant correlation between geographic and genetic distances (rs=0.32; P<0.0001). Integration of molecular and geographic diversity patterns can allow the selection of sites for Tuber and Tuberrelated biodiversity conservation

A realized Tuber &lt;i&gt;magnatum&lt;/i&gt; niche in the upper Sinni area (south Italy)

“…Rubini et al [9] assessed genetic distance of some T. magnatum specimens from Basilicata. Overall, genetic analyses supported a self-fertilization breeding system consistent with the estimates of the within and between population genetic diversity [9,11,13]. However, differentiation due to habitat fragmentation should not be excluded.…”

“…Surprisingly, T. magnatum producing areas are reported as located in central and northern Italy and only "rarely" south of Umbria [8,9]. For the first time Pomarico et al [13] brought to light Basilicata as the southern Italian Region rich in Tuber species. Among the edible species, T. magnatum is common and locally distributed in "Serrapotamo", an area connected with Pollino National Park [13].…”

“…For the first time Pomarico et al [13] brought to light Basilicata as the southern Italian Region rich in Tuber species. Among the edible species, T. magnatum is common and locally distributed in "Serrapotamo", an area connected with Pollino National Park [13]. Rubini et al [9] assessed genetic distance of some T. magnatum specimens from Basilicata.…”

“…Delineating geographic areas characterized by a suitable climate for perennial symbiotic species is a consolidated method in forestry since the early 20th century [1]. The Lauretum cold belt, associated with T. magnatum distribution [13], requires an annual mean temperature from 12˚C to 17˚C, a temperature higher than 3˚C in the coldest month and the average of the yearly minimum temperatures higher than −9˚C [1]. When phytoclimatic conditions are met, geological maps represent an excellent additional tool to identify truffle production areas given that suitable soils (regolithic or residual) depend on the bed-rock type [14].…”

Natural production of Tuber aestivum in central Spain: Pinus spp. versus Quercus spp. brûlés

“…The production points of T. aestivum, known as burns or brûlés, are characterized by clearings in the vegetation, a result of the phytotoxic capacity of the Tuber mycelia (Plattner and Hall, 1995;Hall et al, 2003;Pomarico et al, 2007). Tuber aestivum dominates the ectomycorrhizal populations within their brûlés, excluding other mycorrhizal species.…”