Tuber Aestivum Research Articles

Extracellular Enzymatic Activity of <i>Tuber maculatum</i> and <i>Tuber aestivum</i> Mycelia

Truffle mycelia exhibit a complex interaction pattern with host plants and have been extensively studied over the last years as a source of new bioactive compounds. Fungal enzymes possess a wide use in food industry, confectionaries, textiles and leather industries in order to simplify the processing of raw materials. They are often more stable than enzymes derived from other sources. Tuber maculatum and Tuber aestivum mycelia were tested for enzymes production in Petri dishes solid medium conditions. The results showed that Tuber maculatum produced seven extracellular enzymes (amylase, xylanase, laccase, lipase, peroxidase, cellulase and catalase) while Tuber aes- tivum produced only three enzymes (amylase, peroxidase and catalase).

Complex chemical evaluation of the summer truffle (Tuber aestivum Vittadini) fruit bodies.

Summer truffle ( Tuber aestivum Vittadini) is one of the most important mycorrhizal mushrooms with underground fruit bodies. Formerly the scientific investigations were focused mainly on its specific fragrant constituents. Our work was concentrated on complex chemical characterization including different organic and inorganic components. Summer truffle has middle crude protein, low fat-, and relatively high fiber and chitin contents; its energy level is low. Distribution of protein fractions is characteristic (in % of crude protein): 40.98; 5.91; 3.85; 19.28 and 29.98% for albumins, globulins, prolamins, glutelins and NPN (non protein nitrogen), respectively. We determined soluble oligo- and polysaccharides (9.00 mg/g DM and 49.9 mg/g DM, respectively), as well as the contents of phenoloids and flavonoids (2.8 mg/g DM and 0.093 mg/g DM, respectively). Mineral composition is similar to other mushrooms; four macroelements (K, P, Ca and Mg) give 97.94% of the all mineral content; occurrence of poisonous elements (as As, Cd, V) is not characteristic. Chemical nature of Tuber aestivum (summer truffle) fruit bodies is very characteristic, regarding not only the occurrence of fragrant components but the classical, “usual” components, too. This rare and highly appreciated hypogaeous mycorrhizal fungus belongs to mushrooms of valuable, specific chemical composition.

Phenolic profile and biological activities of black summer truffles (Tuber aestivum Vittad.)

Edible mushrooms from the genus Tuber, a group of mycorrhizal ascomycetous fungi with subterranean fruiting bodies, are particularly appreciated for their unique taste and great economic value. However, their biological activity is still insufficiently explored. The aim of this study was a comprehensive investigation on phenolic profile, antioxidant, anti-inflammatory and cytotoxic activity of black summer truffles (Tuber aestivum Vittad.). Methanol and water extracts, obtained by maceration and Soxhlet extraction, were examined according to previously reported procedures [1]. Forty-five phenolics were studied using LC-MS/MS: presence of seven compounds was confirmed, with the most dominant being p-hydroxybenzoic acid, baicalein and kaempferol. Moderate antioxidant activity was determined through several assays. Examined extracts did not show anti-inflammatory potential regarding inhibition of COX-1 and 12-LOX pathway products synthesis. Nevertheless, extracts exerted prominent cytotoxicity against breast adenocarcinoma (MCF7) tumor cell lines (IC50 ranged from 2.3 to 34.5 µg/mL), as well as notable activity towards HeLa and HT-29 cancer cells. Overall, obtained results support further investigations of phytochemicals and biological activity towards verification of nutraceutical use of black summer truffles.

Ectomycorrhizal communities above and below ground and truffle productivity in a Tuber aestivum orchard

Aim of study: The diversity of ectomycorrhizal fungal communities (EM) above (EMFb) and below (EMMt) ground associated with Quercus cerris L., Q. pubescens Willd., and Pinus nigra J.F.Arnold was analyzed.Area of study: A 20 year-old orchard that produces Tuber aestivum truffles, located a few kilometers from Chiusi della Verna (latitude 43° 41’ 53’’; longitude 11° 56’ 9’’) in Tuscany (central Italy) was observed.Material and Methods: This investigation combined analyses of EMFb, EMMt, T. aestivum productivity, different host trees, and statistical data on community ecology.Main results: The EM communities showed high species richness and differed slightly in relation to both the host tree and their location above or below ground, providing frequent findings of Tricholoma and Tomentella, respectively. Positive correlations were found between the number of truffles and host trees, and between the weight and number of truffles and EMFb.Research highlights: Mycorrhizal fungi and truffle production are not in competition.Key words: Fungal communities; fruiting bodies; morphotypes; Tuber aestivum; competition; Italy.

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

Aim of study: Tuber aestivum is the most widespread edible truffle, with increasing commercial interest. This species can produce carpophores with conifer hosts, in contrast with the inability of Pinus spp. to induce fruiting in other truffle species such as Tuber melanosporum. Therefore the objective is to compare the characteristics and carpophore production of T. aestivum brûlés associated with Pinus spp. versus Quercus spp.Area of study: We studied the natural habitats of T. aestivum in the Alto Tajo Nature Reserve in central Spain.Material and methods: During 5 years, we monitored the production of carpophores and brûlé size of 145 T. aestivum brûlés associated with Pinus nigra subsp. salzmanni and P. sylvestris and Quercus ilex subsp. ballota and Q. faginea hosts. Statistical treatment was performed using the Statistica Program v. 6.Main Results: The size of brûlés associated with Pinus was significantly smaller than that of brûlés associated with Quercus. However, carpophore production per brûlé, and especially for brûlés of similar size, was greater when the host plant was a pine. After accounting for brûlé size, the production of brûlés associated with Pinus spp. was 2.23 (95% CI, between 1.35 and 3.69) and 1.61 (95% CI, between 1.02 and 2.54) times greater than the production of brûlés associated with Quercus faginea and Q. ilex subsp. ballota, respectively.Research highlights: The considerable ability of Pinus nigra subsp. salzmanni and P. sylvestris to form effective brûlés and to produce carpophores of Tuber aestivum in natural conditions was clearly demonstrated, and suggest that those species can be of use in the culture of T. aestivum.Key words: Summer truffle; Tuber aestivum; truffle culture; truffle ecology; Pinus spp.; Quercus spp.

Tuber melanosporum spread within sub-optimal climatic zones is controlled by fruiting triggers and not mycorrhiza survival

<p><em>Tuber melanosporum</em> is the most valuable of all cultivatable truffle species. Farming of this species spans every continent with the exception of Antarctica. <em>Tuber aestivum</em> (syn. <em>T. uncinatum</em>) and <em>Tuber brumale</em> are truffle species that have similar host plant preference and a similar affinity for calcareous soils as <em>T. melanosporum</em>, but occur over a broader geographic zone. The geographic limit of <em>T. melanosporum</em> is thought to be climatically dictated but it is not known whether this is due to an impact on mycorrhizal survival or climatically-derived fruiting triggers. Here, data is compiled from five cultivated research sites in the climatically sub-optimal conditions of the UK in order to address this question. Here we show:</p><p><em>(</em><strong><em>i</em></strong><em>)Tuber melanosporum</em> mycorrhiza can survive and grow in sub-optimal climatic conditions.</p><p>(<strong><em>ii</em></strong>)It is climatically-derived fruiting triggers and not ectomycorrhiza survival that dictate the climatic preferences and geographic spread of <em>T. melanosporum</em>.</p><p>(<strong><em>iii</em></strong>)Important climatic parameters for potential fruiting triggers are sunshine hours, summer rainfall and summer temperatures.</p><p> </p><p>The data presented here not only aid our understanding of the ecological parameters of <em>T. melanosporum</em> but also have a practical application for truffle cultivators in choosing suitable locations for a plantation.</p>

Does the natural “microcosm” created by Tuber aestivum affect soil microarthropods? A new hypothesis based on Collembola in truffle culture

The interactions between fungi and soil fauna are not well known. Some studies suggest that soil microarthropods play an important role in fungi dispersion, but little is still known about the interaction between truffle and soil microarthropods. The aim of this study was to investigate the ability of the truffle Tuber aestivum to modify soil biogeochemistry (i.e. create a zone of scarce vegetation around the host plant, called a burn or brûlé) and to highlight the effects of the brûlé on the soil fauna community. We compared soil microarthropod communities found in the soil inside versus outside the T. aestivum brûlé with the chemistry of soil collected inside versus outside the brûlé. The study was carried out in three Mediterranean areas, two in Italy and one in Spain. The results confirmed the ability of T. aestivum to modify soil biogeochemistry in the brûlé: pH was higher and total organic carbon tended to be lower inside the brûlé compared to outside. Soil fauna communities showed some interesting differences. Some groups, such as Symphyla and Pauropoda, adapted well to the soil; some Collembolan families, and biodiversity and soil quality indices were generally higher outside the brûlé. Folsomia sp. showed higher abundance in the soil of the brûlé compared to outside. The results suggest that some Collembola groups may be attracted by the fungal metabolites produced by T. aestivum, while other Collembola and other microarthropods may find an unfavourable environment in the soil of the brûlé. The next steps will be to confirm this hypothesis and to extend the study to other keys groups such as nematodes and earthworms and to link fluctuations of soil communities with the biological phases of truffle growth.

Phenolic profile, antioxidant, anti-inflammatory and cytotoxic activities of black (Tuber aestivum Vittad.) and white (Tuber magnatum Pico) truffles

The aim of this study was a comprehensive investigation on phenolic profile, antioxidant, anti-inflammatory and cytotoxic activity of the still insufficiently explored black summer truffles (Tuber aestivum Vittad.) and white (Tuber magnatum Pico) truffles. Methanol and water extracts, obtained by maceration and Soxhlet extraction, were examined. Forty-five phenolics was studied using LC–MS/MS: presence of 14 compounds was confirmed, with the most dominant being p-hydroxybenzoic acid, baicalein and kaempferol (T. aestivum), epicatechin and catechin (T. magnatum). Moderate antioxidant activity of both species was determined through several assays. Only T. magnatum showed anti-inflammatory potential by inhibiting COX-1 and 12-LOX pathway products synthesis. Methanol extracts exerted cytotoxicity against some tumour cell lines (HeLa, MCF7, HT-29), besides the prominent activity of water extracts towards breast adenocarcinoma (MCF7). To conclude, these results support further investigations of phytochemicals and biological activity towards verification of nutraceutical use of both species.

Tuber aestivum association with non-host roots.

Mycorrhizal fungi provide direct and functional interconnection of soil environment with their host plant roots. Colonization of non-host plants have occasionally been described, but its intensity and functional significance in complex plant communities remain generally unknown. Here, the abundance of ectomycorrhizal fungus Tuber aestivum was measured in the roots of host and non-host (non-ectomycorrhizal) plants in a naturally occurring T. aestivum colony using a quantitative PCR approach. The roots of non-host plant species found inside the brûlé area were extensively colonized by T. aestivum mycelium, although the levels were significantly lower than those found in host Carpinus betulus roots. However, fungal biomass concentration in the non-host roots was one to two orders of magnitude higher than that in the surrounding soil. This indicates existence of an important biotic interaction between T. aestivum mycelium and the non-host, mostly herbaceous plants. Roots, either host or non-host, thus probably constitute hot spots of T. aestivum activity in the soil ecosystem with as yet uncovered functional significance.

Viability and morphology of Tuber aestivum spores after passage through the gut of Sus scrofa

Abstract Truffles have hypogeous fruit bodies that are dependent on mycophagous animals for spore dispersal. In our study we assessed the effect of passage through the gut of Sus scrofa on the morphology and viability of Tuber aestivum asci and ascospores. Light and Atomic Force Microscopy showed that passage through the gut freed spores from the asci, eroded the walls of free spores and modified their structure but spores were still viable. We believe this was the reason for the observed improvement in forming mycorrhizas with oak. These results confirm the role of wild boars in long distance dispersal of Tuber and support the theory that pigs play a significant role in truffle survival and territorial expansion during climatic changes.

Influence of the late harvest period on reproductive spore quality of Burgundy truffles (Tuber aestivum Vittad.)

DOI: 10.15414/afz.2014.17.01.11-17 Received 24. January 2014 ǀ Accepted 27. February 2014 ǀ Available online 8. April 2014 The work presents new findings about the influence of the late harvest period on reproductive spore quality of Burgundy truffles ( Tuber aestivum Vittad.) assessed by microscopic method and by inoculation experiments with hornbeam Carpinus betulus L. seedlings. Carpophore samples from one locality were collected in two terms in each month from November to January. Reproductive quality of spores was assessed by microscopic method. The presence of mycorrhiza on the roots was assessed by morphometric analysis. Quality of spores in winter decreased rapidly. Percentage of plants with Tuber aestivum mycorrhiza in the tested variants ranged from 19.72% (early November) to 2.98% (end of January). In variants with fruiting bodies collected in November observed level mycorrhized roots were statistically highly significant different from variants inoculated by carpophores from January and December. Lower percentage of Tuber aestivum mycorrhiza on root system of hornbeam seedlings in late periods of carpophores collection significantly influenced length of root system, while the length of stems was not statistically significant. Keywords : Burgundy truffle, hornbeam, reproduction quality, mycorrhization

Phylogeny and phylogeography of the Tuber brumale aggr.

The Tuber brumale (winter truffle) is a black truffle reported from most European countries, belonging to the Melanosporum group. Its significance in the economy is ambivalent as the winter truffle has been shown to be a frequent contaminant species in the orchards of the Perigord truffle and occasionally in those of the summer truffle, yet owing to its delicate fragrance, its trade is worthy of note. The phylogeny and phylogeography of economically important truffles are relatively well-explored; however, no thorough research has been published on these aspects of the winter truffle. Therefore, here, we report the first phylogeographic analyses based on samples representing the entire distribution of the species. ITS sequences were used in this survey for haplotype and coalescent analyses, while phylogenetic analyses were based on the ITS, LSU and PKC loci. According to all loci, the samples clustered into two big clades imply the existence of two phylogenetic species. Based on our results, one of these appears to be endemic to the Carpathian Basin. In the other more widespread species, two main phylogeographic groups can be distinguished that show east-west separation with a zone of overlap in the Carpathian Basin, suggesting that they survived the latest glacial period in separate refugia.

Environmental conditions that promote the occurrence of truffles (Tuber spp.) on historical sites in Poland

Abstract This article highlights historical data regarding truffles’ occurrence in Poland. Along with the soil parameters the plant communities at the sites were studied. The results of the chemical soil analyses showed that the soil pH in water on 5 sites was acidic (from 4.3 to 6.1), and only in one, Wiązowna, was the pH (7.2) conductive to truffles development. Similarly, the content of calcium carbonate (CaCO3) in soil samples was low (from 0 to 0.03%), except for Wiązowna, where CaCO3 was 0.12%. Among the 24 reported species of trees and shrubs, 7 species were host-plants of summer truffle (Tuber aestivum Vitt.). Out of the 7 species, oak and hornbeam were present at four localisations. Across the sites, 31 species of ground-layer plants were identified. Among these, Epipactis helleborine was only one host-species of summer truffle. Our findings indicate that formation of truffles fruiting-bodies depends on specific habitat characteristics. The key factors determining this process are soil parameters, such as: texture, pH and calcium content. Our inventory showed that the sites we studied still persist as natural stands, although only one of them seems to be favorable for truffles development: this site is located in Wiązowna, where soil is of pH 7.2 and E. helleborine, (host species for truffles from Orchidaceae) is found, fulfills the environmental requirements of truffles

Cultivation of Mediterranean species of Tuber (Tuberaceae) in British Columbia, Canada

Based on an assessment of soil and climatic conditions in British Columbia (BC), the Truffle Association of British Columbia (TABC) determined that the cultivation of Mediterranean Tuber melanosporum and Tuber aestivum might be possible in the warmer parts of the province. With the cooperation of independent truffle growers, TABC assessed the colonization of host tree roots collected from eight truffle orchards planted 2-7 years earlier using morphological and molecular criteria. Both Tuber species persisted on the roots of inoculated trees in six of the eight truffle orchards studied. The identity of Tuber ectomycorrhizas that had been characterized morphologically as differing from those of T. melanosporum and T. aestivum were determined using DNA sequence analysis to belong to three species of truffles native to the Pacific Northwest. One of those species, Tuber anniae, had been previously reported from BC, but the other two, Tuber menseri nom. prov. and Tuber beyerlei, are reported here from BC for the first time. Recently, production of three Périgord black truffles in one truffle orchard and one Burgundy truffle in another orchard demonstrates that these truffles are able to fruit in BC.

The role of pH in Tuber aestivum syn. uncinatum mycorrhiza development within commercial orchards

The accepted advice when establishing a plantation of <em>Tuber aestivum</em> syn. <em>uncinatum</em> is that young inoculated trees should be planted on calcareous soils with a naturally high pH level. When a site is employed that has a naturally low pH level, lime is often applied to raise the pH to a considered ideal level of c.7.5. However, this may not be the correct approach. Here we present data from 33 data points taken from commercial truffle orchards in England, UK. Soil pH is correlated to <em>Tuber aestivum</em> syn. <em>uncinatum</em> mycorrhiza survivorship and development. The optimal observed pH was 7.51 but the actual optimal pH for cultivation may be higher. Sub optimal pH levels lead to a reduction of <em>Tuber aestivum</em> syn. <em>uncinatum</em> mycorrhiza. This reduction is not permanent and mycorrhization levels may be improved within a 12 month period by amending the soil pH. The importance of understanding the interaction of pH with other variables and the results in relation truffle cultivation are discussed.

Europe, a continent with high potential for the cultivation of the Burgundy truffle (Tuber aestivum/uncinatum)

The Burgundy truffle (<em>Tuber aestivum/uncinatum</em>) grows, in Europe, in the most varied soils from a physical and chemical viewpoint. The only common point is the presence of a minimum level of exchangeable calcium in the soil. The truffle soils in Europe can be classified in two categories: the soils coming directly from the parent rock, and those formed from deposits covering the parent rock. The first group corresponds to most traditional truffle areas , France, Italy and Spain. It is also true for some soils from Ireland to Eastern Europe (Romania, Bulgaria), from Southern Europe (Greece, former Yugoslavia) to Northern Europe (Sweden, Baltic countries). The sedimentary layers that cover most areas are from the secondary and tertiary era. The primary parent rocks are less frequent. The second group means quaternary or recent alluviums covering the parent rock on huge surfaces and at great depth sometimes. They characterize mainly countries Eastern and Northern Europe. By bringing within reason limestone, it is possible to cultivate <em>T. aestivum/uncinatum</em> on sedimentary soils non-calcareous or decalcified or even on soils issued from magmatic rocks (granite) or metamorphic (schists). The possibilities of truffle cultivation in Europe are therefore enormous, the limiting factors not being the soil but the climate.

Changes of hypogeous funga in the Carpathian-Pannonian region in the past centuries

The exploration of hypogeous fungi in the Carpathian-Pannonian region speeded up in the past decades, owing to the widespread of truffle hunting with dogs. As a result, not only several new species were found in the region, but our view of the frequency of truffles also changed fundamentally. It became evident that <em>Tuber aestivum</em>, <em>T. brumale</em>, <em>T. macrosporum</em>, <em>T. magnatum</em>, <em>T. mesentericum </em>and <em>Mattirolomyces terfezioides </em>can be collected in commercial quantity. Among the dog preferred hypogeous fungi (DPH) several species, earlier believed to be rare like <em>Octaviania asterosperma </em>and <em>Stephensia bombycina</em>, also occurred. The taxonomic alterations and revisions brought about changes in the list of hypogeous fungi, and further changes are expected from molecular taxonomy research on a number of genera at present.

Ecological characteristics of a Hungarian summer truffle (Tuber aestivum Vittad.) producing area

Hungary has outstanding environment for natural truffle production in some regions including plain and hilly areas. The most famous of all the natural summer truffle (<em>Tuber aestivum</em> Vittad.) habitats is the commonly called Jászság region. This area is situated in the middle of Hungary, between river Danube and Tisza. The flatland area is basically covered by river alluviums with main soils of chernozems, fluvisols, solonchaks and arenosols. Climate of the region is typically continental: warm and dry summers and cold winters vary. The area is traditionally of agricultural use, although strong afforestation was made in the late 1950’s. The English oak (<em>Quercus robur</em> L.) populations planted at that time gave a basis for current excellent truffle production. Nowadays the region has proved to be the best natural summer truffle (<em>T. aestivum</em>) producing area of Hungary with early season opening (June) and high quality truffles as early as August. In the research the best truffle producing forest blocks were selected for ecological investigation. Results of the detailed site description showed uniform climate characteristics and dominance of English oak (<em>Q. robur</em>) or mixed English oak-Turkey oak (<em>Quercus cerris</em> L.) forests. Soil types revealed differences from earlier findings: dominance of gleysols and water affected chernozems was declared. Soil chemical parameters are in accordance with literature data: pH, organic matter and active carbonate content of the examined soils fall within the range indicated as the requirement of <em>T. aestivum</em>.

Site characteristics of Tuber magnatum in Greece

Day after day it is being demonstrated that Greece hides a buried treasure in its forests. The wild black truffles <em>Tuber aestivum, T. uncinatum, T. brumale </em>and <em>T. melanosporum </em>and the white truffle <em>T. borchii </em>and recently <em>T. magnatum </em>are picked in a variety of forest ecosystems all over the country. The information which has been collected has initiated a national programme on truffle cultivation which, so far, has immense appeal, especially among young farmers. The discovery of carpophores of <em>T. magnatum</em>, the most valued white truffle in the market, triggered the interest in studying the site characteristics, botanical and pedological, in order to help farmers to cultivate the species in similar sites. All carpophores were found under hornbeam (<em>Carpinus orientalis</em>) along the banks of a creek on alluvial sediment. Soil analyses of four soil samples from truffle nests showed a narrow range of values of pH in water (7.57–7.78) and 1N KCL (6.94–7.07) and a similar granulometric soil texture.

Assessing genetic resources of summer truffle in Slovakia

A study of summer truffle genetic resources, their description and evaluation of economically important traits in Slovak natural truffiéres started since 2005. Draft of national descriptor list has been developed to manage truffle genetic resources collected in the information system "Tuber Aestivum/ Uncinatum Phenotype Data" (TAUPD). Revision was performed in TAUPD to increase effectiveness of truffle breeding process.