A global meta‐analysis of Tuber ITS rDNA sequences: species diversity, host associations and long‐distance dispersal

Abstract

Truffles (Tuber) are ectomycorrhizal fungi characterized by hypogeous fruitbodies. Their biodiversity, host associations and geographical distributions are not well documented. ITS rDNA sequences of Tuber are commonly recovered from molecular surveys of fungal communities, but most remain insufficiently identified making it difficult to determine whether these sequences represent conspecific or novel taxa. In this meta-analysis, over 2000 insufficiently identified Tuber sequences from 76 independent studies were analysed within a phylogenetic framework. Species ranges, host associates, geographical distributions and intra- and interspecific ITS variability were assessed. Over 99% of the insufficiently identified Tuber sequences grouped within clades composed of species with little culinary value (Maculatum, Puberulum and Rufum). Sixty-four novel phylotypes were distinguished including 36 known only from ectomycorrhizae or soil. Most species of Tuber showed 1-3% intraspecific ITS variability and >4% interspecific ITS sequence variation. We found 123 distinct phylotypes based on 96% ITS sequence similarity and estimated that Tuber contains a minimum of 180 species. Based on this meta-analysis, species in Excavatum, Maculatum and Rufum clades exhibit preference for angiosperm hosts, whereas those in the Gibbosum clade are preferential towards gymnosperms. Sixteen Tuber species (>13% of the known diversity) have putatively been introduced to continents or islands outside their native range.

Two new Terfezia species from Southern Europe

“…The application of novel molecular methods to hypogeous fungal group, on which desert truffles can be found, allows the discovery of new species. The finding of undiscovered species within the genera of desert truffles will rise throughout the coming years (Bordallo & Rodríguez 2014), similar to those carried out on genera like Tuber (Bonito et al 2010).Recently, five species of Terfezia have been reported from the Iberian Peninsula (Bordallo et al 2013) and one from the Canary Islands (Bordallo et al 2012). The difficulty of sampling desert truffles implies their discovery only in specific locations.…”

SSR-based identification of genetic groups within European populations of Tuber aestivum Vittad

“…More than 200 Tuber species have been reported worldwide (Bonito et al 2010(Bonito et al , 2013, and to date, 32 truffle species have been described in Europe (Ceruti et al 2003), many of which are precious edible fungi. As ECM fungi, truffles play an important role in woodland ecosystems specifically for tree growth (Smith and Read 2008).…”

Gozd in les: 70 let

“…V zadnjih deset letih smo na Gozdarskem inštitut Slovenije zbrali preko 1200 vzorcev iz rodu Tuber in še vsaj 500 vzorcev iz drugih rodov podzemnih gliv (Grebenc et al, neobjavljeno), mnoge od katerih smo analizirali tudi z molekularnimi pristopi. Filogenetska analiza okoli 500 vzorcev različnih morfoloških vrt gomoljik je pokazala večjo pestrost rodu, kot bi sklepali na osnovi morfoloških določitev (Marjanović et al, 2010;Grebenc et al, 2015a, b), kar je v skladu z opažanjem velike filogenetske pestrosti rodu Tuber, v katerem je na globalni ravni zabeleženih vsaj 180 različnih vrst (Bonito et al 2010). Velika genetska pestrost predstavlja vir morebitnih novih vrst tako za Slovenijo, kot za širše področje Dinaridov in globalno (Milenković et al 2015).…”