The genus Tuber comprises ectomycorrhizal fungal species producing belowground ascomata, including the gastronomically most prominent hypogeous fungi. Since the discovery and description of new species are ongoing, the proportion of undescribed species can be considerable and the taxonomy of the genus goes often through changes. The taxonomy of the genus Tuber would therefore benefit from a periodic review. Tuber species described in Europe in recent decades include Tuber regianum, T. bernardinii and T. magentipunctatum. The common characteristics of these three species are the relatively small-sized spores with alveolate-reticulate ornamentation, a high number of spores per ascus (most frequently 6–8 spores) and small-sized ascomata with a verrucose-papillate or smooth surface. The present study aimed at examining the morphology and ecology of the three species, and providing a detailed taxonomic description of the Regianum clade using a multilocus phylogenetic analysis. In addition to this, we examined whether the apparently plesiomorphic morphological character states of this phylogenetically basal clade are the result of the conservation of ancestral character states. Our results show that in the case of certain morphological traits of the Regianum clade, the apparently plesiomorphic character states are indeed retained ancestral states, while in others, they are convergently reappeared ones. Furthermore, taking an overlook at all Tuber clades, we found that some morphological characters, such as spore length, number of spores per ascus and ascus length, changed together in the same evolutionary patterns, while others transformed in different ways within the genus.

Tuber aestivum is a key truffle species with significant ecological and economic value. Despite its importance, plantation success can be influenced by soil pH, host plants, and undesired fungi. This study examines how soil pH and host plants influence mycorrhization trends in T. aestivum plantations across six plant species in eight Hungarian settlements, using root sampling and DNA analysis to assess plantations at three and six years of age. Tuber aestivum achieved over 30% mycorrhization, with Carpinus betulus showing the highest levels. DNA analysis identified eight undesired mycorrhizal fungi, with Suillus spp. (42.9%) and Scleroderma spp. (31.4%) being the most prevalent. The study found that T. aestivum preferred a soil pH of around 7.6, while undesired fungi thrived in slightly acidic conditions. Additionally, soil pH significantly and positively influenced T. aestivum mycorrhization; however, factors such as plantation age also contributed to mycorrhization trends. While mycorrhization by undesired fungi decreased with higher soil pH, it increased as plantations matured from three to six years. These findings highlight the need for the effective management of soil pH and the control of undesired fungi to optimize T. aestivum mycorrhization, emphasizing the importance of targeted strategies and further research for sustainable truffle cultivation.

Tuber melanosporum is one of the most economically important truffle species. Besides harvesting from its natural habitats, this truffle can also be extensively grown through artificial cultivation. However, the natural habitat of T. melanosporum has drastically declined, and the demand for the truffle in society is rapidly increasing. Therefore, enhancing production in truffle orchards by seeking new places for the establishment and regularly monitoring its adaptability might be an effective method for ensuring the sustainable productivity of the species. As a truffle science, recent information is important to further success in the growth of this truffle species. This study reports mycorrhization level and ascocarp production in two truffle plantations in Hungary. The estimated mycorrhization levels of the host plants were 43.36% in Biatorbágy and 42.93% in Jászszentandrás plantations. In March 2020, the 6-year-old and 18-year-old T. melanosporum plantations yielded around 100 g and 980 g of ascocarps, respectively. In general, adaptation of mycorrhizal seedlings in Hungary may become more effective as present management practices improve.

We hypothesized that Tuber melanosporum colonization enhances growth and photosynthetic performance in Corylus avellana seedlings. Forty-eight seedlings were assessed for root colonization (stereomicroscopy, ITS sequencing) and photosynthetic traits (Li-6800F) under short-term disturbed and undisturbed rhizosphere conditions. Mycorrhizal colonization was found in 97.9% of seedlings (47/48). The mean colonization was 33.1% (SD = 16.1), 16.7% of seedlings showed more than 50% colonization per seedling, and 65.0% showed more than 30% colonization per seedling. Colonization declined with root depth and correlated with seedling length (r = 0.371, p = 0.01). In disturbed roots, longer root length predicted higher Gsw (r = 0.60), PhiCO₂ (r = 0.77), and PhiPSII (r = 0.70), while collar diameter negatively affected transpiration (r = −0.60). In undisturbed roots, collar-proximal colonization improved PhiPSII (r = 0.69, p = 0.02). Undisturbed seedlings showed ~2× higher CO₂ assimilation, stomatal conductance, quantum yield, and transpiration. These findings confirm that T. melanosporum enhances seedling physiology, especially under undisturbed conditions.

Hungary has some of the best-researched hypogeous fungal flora in Europe, with a large number of genera and species already having been discovered in this country. In this study, we performed morphological and molecular analysis of unidentified hypogeous fungi samples collected from Hungary. We confirmed that they belong to the hypogeous earthstar species Geastrum nadalii (Paz et al., 2024), marking the first report of this species in this country and in a continental climate. We also assume that the habitat preference of this mushroom species is similar to the habitat preference of Mattirolomyces terfezioides, with both occurring in planted non-native Robinia pseudoacacia forests, suggesting that these are secondary habitats for these species. We also conclude that this Mediterranean species has appeared only recently in the Hungarian mycota.