Ascoma genotyping and mating type analyses of mycorrhizas and soil mycelia of Tuber borchii in a truffle orchard established by mycelial inoculated plants

Abstract

Summary Tuber borchii (the Bianchetto truffle) is a heterothallic Ascomycete living in symbiotic association with trees and shrubs. Maternal and paternal genotype dynamics have already been studied for the black truffles Tuber melanosporum and Tuber aestivum but not yet for T. borchii. In this study, we analysed maternal and paternal genotypes in the first truffle orchard realized with plants inoculated with five different T. borchii mycelia. Our aims were to test the persistence of the inoculated mycelia, if maternal and/or paternal genotypes correspond to inoculated mycelia and to assess the hermaphroditism of T. borchii. The mating type of each isolate as well as those of mycorrhizas, ascomata and extraradical soil mycelia was determined. Moreover, simple sequence repeat (SSR) profiles of maternal and paternal genotypes were assessed in 18 fruiting bodies to investigate the sexual behaviour of this truffle. The maternal genotypes of the fruiting bodies corresponded to those of the inoculated mycelia with only two exceptions. This confirmed that the inoculated mycelia persisted 9 years after plantation. As regards paternal partner, only two had the same genotype as those of the inoculated mycelia, suggesting hermaphroditism. Most of the new paternal genotypes originated from a recombination of those of inoculated mycelia.

Hidden fairy rings and males—Genetic patterns of natural Burgundy truffle (Tuber aestivum Vittad.) populations reveal new insights into its life cycle

“…Several studies of Périgord truffle (T. melanosporum) populations revealed a strong mating-type aggregation with spatial structuring of maternal individuals carrying the opposite MAT locus (De la Varga et al, 2017;Murat et al, 2013;Rubini et al, 2011a;Taschen et al, 2016). The same was recently described in a T. borchii plantation (Leonardi et al, 2019). Such aggregation of mating types seems to occur in the Burgundy truffle as well, but at a lesser prevalence with mixed patterns based on current and previous studies.…”

Two ectomycorrhizal truffles, Tuber melanosporum and T. aestivum, endophytically colonise roots of non‐ectomycorrhizal plants in natural environments

“…Males are ephemeral, cover small areas and are absent from surrounding ECM root tips; female are more often perennial, spatially larger and colonise surrounding ECM trees. These features, together with high inbreeding, were demonstrated for T. melanosporum (Selosse et al, 2013;Taschen et al, 2016;De la Varga et al, 2017), and possibly for T. borchii (Leonardi et al, 2019): this study demonstrates that sexual dimorphism also applies to T. aestivum.…”

Desert truffle genomes reveal their reproductive modes and new insights into plant–fungal interaction and ectendomycorrhizal lifestyle

“…So far, MAT loci have not been identified in any desert truffle, and therefore their mating mode (homothallism vs heterothallism) is unknown (Murat et al ., 2018). As shown for Tuber melanosporum (Rubini et al ., 2011, 2014; Linde & Selmes, 2012; Zampieri et al ., 2012; Murat et al ., 2013; Le Tacon et al ., 2014), Tuber borchii (Mello et al ., 2017; Leonardi et al ., 2019), and Tuber aestivum (Molinier et al ., 2016; Splivallo et al ., 2019), the characterization of the MAT locus has been critical for disclosing the reproduction mode of these fungi and, in turn, for designing new cultivation strategies.…”