Insect-truffle interactions – potential threats to emerging industries?

Truffle harvests are declining in Europe, due to droughts, and this offers an opportunity for production to be developed in countries such as the UK and Poland, where rainfall tends to be higher. Drier Mediterranean summers seem to be associated with a decrease in the harvest of the Périgord truffle (Tuber melanosporum) in Spain, France and Italy. However, other species, for example the Burgundy truffle (Tuber aestivum) offer opportunities for production in the more temperate environments north of the Alps. Truffles across Europe can be infested by insect larvae, seriously reducing their economic and culinary quality. Here, using a combination of literature sources and a field survey, we present a commentary on insects attacking truffles, aiming to highlight those species that could be potential pests in the British and Polish emergent industries. There is a remarkable disparity in coincidence of records of insects and truffles in these countries, yet a survey in Poland confirms that insects can be abundant. We discuss reasons for this disparity and suggest that biochemical methods could easily be developed for detection of the truffles and their attackers.     

Genetic structure of <Emphasis Type="Italic">Tuber mesentericum</Emphasis> Vitt. based on polymorphisms at the ribosomal DNA ITS

Tuber mesentericum fruit bodies are in increasing demand on the food market and are an important economic resource for southern Italy, their major production area. Because molecular studies on this truffle species are very scarce, we analyzed ITS1 and ITS2 nucleotide variability of 126 ascocarps of T. mesentericum collected in different European areas, mainly southern Italy. The results of haplotype distribution, analysis of molecular variance, and spatial analysis of molecular variance analyses show strong genetic structuring of the samples collected in the different geographic areas, confirmed by parsimony and distance analyses. In particular, the Italian samples seem to be a well-distinguished group.     

Fine‐scale spatial genetic structure analysis of the black truffle Tuber aestivum and its link to aroma variability

Truffles are symbiotic fungi in high demand by food connoisseurs. Improving yield and product quality requires a better understanding of truffle genetics and aroma biosynthesis. One aim here was to investigate the diversity and fine‐scale spatial genetic structure of the Burgundy truffle Tuber aestivum. The second aim was to assess how genetic structuring along with fruiting body maturation and geographical origin influenced single constituents of truffle aroma. A total of 39 Burgundy truffles collected in two orchards were characterized in terms of aroma profile (SPME‐GC/MS) and genotype (microsatellites). A moderate genetic differentiation was observed between the populations of the two orchards. An important seasonal and spatial genetic structuring was detected. Within one orchard, individuals belonging to the same genet were generally collected during a single season and in the close vicinity from each other. Maximum genet size nevertheless ranged from 46 to 92 m. Geographical origin or maturity only had minor effects on aroma profiles but genetic structuring, specifically clonal identity, had a pronounced influence on the concentrations of C₈‐ and C₄‐VOCs. Our results highlight a high seasonal genetic turnover and indicate that the aroma of Burgundy truffle is influenced by the identity of single clones/genets.     

Effect of Conidiobolus coronatus on the Cuticular and Internal Lipid Composition of Tettigonia viridissima Males

Conidiobolus coronatus is an entomopathogenic fungus which has a potential as a biological control agent of insects. The cuticular and internal lipid composition of infected and noninfected Tettigonia viridissima males were analyzed by GC/MS. A total of 49 compounds were identified in the infected and noninfected males, including fatty acids, fatty acid methyl esters (FAMEs), n‐alkanes, alcohols, sterols, and other organic compounds. The most abundant components of the cuticular and internal lipids of the insects were fatty acids. After exposure to C. coronatus, the cuticular lipids of the T. viridissima males contained 17 free fatty acids from C(8) to C(22), while the cuticular lipids of the noninfected insects contained only 15 fatty acids from C(12) to C(24). The cuticular and internal lipids of both the infected and the noninfected males also contained five FAMEs from C(15) to C(19), seven n‐alkanes from C(25) to C(34), five alcohols from C(16) to C(25), five sterols, and the following six other organic compounds: azelaic acid, phenylacetic acid, glutaric acid, benzoic acid, sebacic acid, and glycerol. The compounds which were present only in the cuticular lipids of the infected males could be due to fungal infection.     

Spatial distribution and ecological variation of re-discovered German truffle habitats

Several truffle species (Tuber spp.) are highly prized by chefs and gourmets with some commanding prices of up to €9.000 kg^?1 on international markets. Their ecological drivers and geographical patterns, however, often remain a puzzle. Truffle species in Germany are classified as Very Rare or even Extinct on the national Red Lists, while historical literature described their sporadic existence. Here we present evidence of seven Tuber species (T. aestivum, T. brumale, T. excavatum, T. fulgens, T. macrosporum, T. mesentericum, T. rufum), discovered at 121 sites in Southwest Germany. The valuable Burgundy truffle (T. aestivum) occurred at 116 sites. An unexpected abundance of Tuber spp. associated with 13 potential host plants along wide ecological gradients in a region far outside the traditional Mediterranean truffle foci in France, Italy and Spain, is likely indicative of possible responses to climate change, and also suggests ample truffle cultivation potential north of the Alpine arc.     

Chemical Diversity and Antimicrobial Activity of Volatile Compounds from Zanthoxylum zanthoxyloides Lam. according to Compound Classes,Plant Organs and Senegalese Sample Locations

The chemical diversity of Zanthoxylum zanthoxyloides growing wild in Senegal was studied according to volatile compound classes, plant organs and sample locations. The composition of fruit essential oil was investigated using an original targeted approach based on the combination of gas chromatography (GC) and liquid chromatography (LC) both coupled with mass spectrometry (MS). The volatile composition of Z. zanthoxyloides fruits exhibited relative high amounts of hydrocarbon monoterpenes (24.3 – 55.8%) and non‐terpenic oxygenated compounds (34.5 – 63.1%). The main components were (E)‐β‐ocimene (12.1 – 39%), octyl acetate (11.6 – 21.8%) and decanol (9.7 – 15.4%). The GC and GC/MS profiling of fruit essential oils showed a chemical variability according to geographical locations of plant material. The LC/MS/MS analysis of fruit oils allowed the detection of seven coumarins in trace content. The chemical composition of fruit essential oils was compared with volatile fractions of leaves and barks (root and trunk) from the same plant station. Hexadecanoic acid, germacrene D and decanal were identified as the major constituents of leaves whereas the barks (root and trunk) were dominated by pellitorine (85.8% and 57%, respectively), an atypic linear compound with amide group. The fruit essential oil exhibited interesting antimicrobial activities against Staphylococcus aureus and Candida albicans, particularly the alcohol fraction of the oil.     

Essential Oils from Anthemis maritima Flowers: Infraspecific Variability along the Adriatic Coast (Italy)

The hydrodistilled essential oils (EOs) from flowers of five Adriatic populations of Anthemis maritima were analyzed by GC‐FID and GC/MS. Anthemis maritima is a psammophilous plant living generally on coastal sand dunes but occasionally on sea cliffs and shingle beaches. A total of 163 chemical compounds were identified, accounting for 90.5% of the oils. The main classes of compounds represented in the EOs were monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpene hydrocarbons, oxygenated sesquiterpenes, and terpene esters.The multivariate chemometric techniques, in particular cluster analysis and principal coordinate analysis, used to classify the samples, highlighted three different chemotypes linked to a geographic origin. One group living in northern Italy was characterized by the highest content of β‐pinene, γ‐terpinene, and β‐caryophyllene, a second chemotype was in central Italy with the highest amount of trans‐chrysanthenyl acetate and a third group living in southern Italy with a more heterogeneous volatile profile was characterized by the highest values of cis‐chrysanthenyl acetate, trans‐chrysanthenyl isobutyrate, cis‐carveol propionate, α‐zingiberene, and cubenol. Moreover, the comparison of the Adriatic populations with the Tyrrhenian samples, analyzed in a previous research, showed that cubenol (absent in all the Tyrrhenian populations) and (E)‐β‐farnesene (absent in all the Adriatic samples) play a crucial role in discriminating the Italian populations.     

Bacteria associated with truffle‐fruiting bodies contribute to truffle aroma

Truffles, symbiotic fungi renown for the captivating aroma of their fruiting bodies, are colonized by a complex bacterial community of unknown function. We characterized the bacterial community of the white truffle Tuber borchii and tested the involvement of its microbiome in the production of sulphur‐containing volatiles. We found that sulphur‐containing volatiles such as thiophene derivatives, characteristic of T. borchii fruiting bodies, resulted from the biotransformation of non‐volatile precursor(s) into volatile compounds by bacteria. The bacterial community of T. borchii was dominated by α‐ and β‐Proteobacteria. Interestingly, all bacteria phyla/classes tested in this study were able to produce thiophene volatiles from T. borchii fruiting body extract, irrespective of their isolation source (truffle or other sources). This indicates that the ability to produce thiophene volatiles might be widespread among bacteria and possibly linked to primary metabolism. Treatment of fruiting bodies with antibacterial agents fully suppressed the production of thiophene volatiles while fungicides had no inhibitory effect. This suggests that during the sexual stage of truffles, thiophene volatiles are exclusively synthesized by bacteria and not by the truffle. At this stage, the origin of thiophenes precursor in T. borchii remains elusive and the involvement of yeasts or other bacteria cannot be excluded.     

Tuber magnatum Pico, a species of limited geographical distribution: its genetic diversity inside and outside a truffle ground

The aim of this work was to clarify the genetic structure of the ectomycorrhizal fungus, Tuber magnatum Pico, in a natural truffle ground located in north Italy. Ascomata of this population of T. magnatum were collected over a period of up to 5 years. For comparative analysis, T. magnatum fruit bodies of different geographical origin were also considered. We used single locus markers, such as the variable region of ribosomal genes (ITS), the beta-tubulin gene and sequence-characterized amplified regions (SCAR), as tools to identify single-nucleotide polymorphisms (SNPs). On the basis of the molecular results, which were indirectly supported by a karyological analysis, a self-fertilization mechanism is suggested. A SCAR region was polymorphic within the samples of the truffle ground, leading to the identification of two genotypes. In addition, both the SCAR and the ITS proved to be polymorphic among samples coming from different geographical regions, revealing a genetic differentiation in T. magnatum.     

Parasitic microfungi of the Tatra Mountains. 3. <Emphasis Type="Italic">Spermosporina gymnadeniae</Emphasis> (Hyphomycetes): species new to Slovakia and new records from Poland

Spermosporina gymnadeniae (Hyphomycetes) on Gymnadenia sp. (Orchidaceae) collected in the Polish part of the Tatra Mts was described in 2003. The fungus was recently found at new localities in Poland and Slovakia. It was recorded on Gymnadenia conopsea s.l. and Dactylorhiza fuchsii, which are new hosts of this parasite. The fungus is described and additional illustrations are provided.     

Ectomycorrhizal fungi with edible fruiting bodies 3.Tuber magnatum, tuberaceae

The Italian white truffle(Tuber magnatum Pico) forms mycorrhizal relationships, with the roots of, for example, poplars, willows, oaks, aspen, alder and hazelnut in Northern Italy and in small areas of Southern France, Switzerland and Yugoslavia. Its fruiting bodies, which are harvested in autumn and early winter, have a strong aroma and taste and are much sought-after by chefs and gourmets. Because they do not preserve well, good quality Italian white truffle is unavailable for much of the year. The vegetation, climate and soils where T. magnatum grows in Italy are described and compared with those found in similar areas in New Zealand. Market information and methods for cultivatingT. magnatum are also presented.     

CALENDAR OF EVENTS

Abstract

Exposure of the general population to polycyclic aromatic hydrocarbons (PAH) is ubiquitous. The aim of this study was to analyze biomarkers associated with the uptake of PAH in 428 non-smoking women from ?odz (Poland), Viterbo (Italy), Belgrade (Serbia) and from the Pan?evo area, where the petrochemical complex was destroyed by the air raids in 1999. Urinary excretion of PAH metabolites was lowest in Italian women, intermediary for Serbian and highest in Polish women, who predominantly excreted hydroxy phenanthrenes as metabolites of phenanthrene. Bulky DNA adduct levels were highest in Italian and Polish women. Genotype or PAH ambient air levels could not explain the dissimilarities between the study groups with respect to biomarker patterns, which probably reflected differences in life style-associated factors.     

Genetic Variability of Hymenoscyphus pseudoalbidus on Ash Leaf Rachises in Leaf Litter of Forest Stands in Poland

Two hundred and thirty cultures of Hymenoscyphus pseudoalbidus were obtained from ascospores created in apothecia on the previous years' ash leaf rachises in the stand floor. Fruiting bodies of the pathogen were collected in four regions of Poland differing by geographical location, the altitude above sea level and climatic conditions. Isolates were identified based on the sequences of ribosomal DNA (ITS1‐5.8S‐ITS2) and the calmodulin gene. Only the presence of H. pseudoalbidus was identified in the decaying ash stands in Poland; morphologically similar, saprotrophic species of H. albidus was absent. Intrapopulation and interpopulation genetic variability of isolates was determined based on 84 RAMS markers obtained using four primers. Genetic variability of the fungus populations, measured by the Dice coefficient of genetic similarity and the Shannon coefficient of genetic diversity, decreased along with a decrease in the location of isolate collection area above sea level. A significant dependency was shown between intrapopulation genetic variability of isolates and altitude of regions above sea level. The Mantel test excluded existence of dependence between geographical and genetic distance among populations (r = ?0.038, P = 0.55). A significant correlation was found between the genetic distances of individuals within populations and locations above sea level. Based on PCA and geographical location of populations, it was shown that populations create four distinct groups. amova showed that a majority of total genetic variability (65.80%) constitutes intrapopulation variability. Variability between populations was high (28.7%), and individual regions had a smallest influence (5.5%) on the level of total variability.     

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.     

Chemical Composition and Antioxidant Activity of Tuber indicum from Different Geographical Regions of China

Tuber indicum, an endemic truffle species in eastern Asian, is an edible mushroom that is both an important export and widely distributed across China. Many existing studies on truffles focus on analyzing their taxonomy, population genetics, volatile organic compounds and artificial cultivation of the truffles, while little information is available about their nutrient composition and pharmacological activity, especially the relationship between chemical composition in ascocarps and their geographic distributions. This study presents a comprehensive investigation of the chemical composition of T. indicum, including free sugars, fatty acids, organic acids, phenolic acids, flavonoids, and polysaccharides, and tracks the antioxidant activity of T. indicum ascocarps collected from five geographical regions of four provinces in P. R. China: Hebei, Tibet, Yunnan, and Liaoning province. Our results showed that T. indicum collected from Qujing, Yunnan province, possessed the highest amount of free sugars (23.67 mg/g dw), total flavonoids (2.31 mg/g dw), total phenolics (4.46 mg/g dw) and the highest DPPH and ABTS radical‐scavenging activities. The amount of water‐soluble polysaccharides was the highest (115.24 mg/g dw) in ascocarps from Tibet, the total organic acids was the highest (22.073 mg/g dw) in ascocarps from Gongshan, and polyunsaturated fatty acids were most abundant in those from Hebei province. This study reveals that the quantity of chemical compounds in T. indicum varies by geographical origin. Detecting differences in chemical composition may provide important data for understanding the relationship between environmental factors and truffle formation, as well as quality evaluation of the commercial species T. indicum throughout China.     

Conservation genetics of highly isolated populations of the xerothermic beetle Crioceris quatuordecimpunctata (Chrysomelidae)

Xerothermic species are rare and threatened in central and eastern Europe. In light of the continuing loss of steppe‐like habitats due to anthropogenic fragmentation and degradation, the evaluation of genetic variation in populations inhabiting them is of immediate importance if appropriate conservation measures are to be undertaken. Here we report on the genetic diversity of the rare leaf beetle Crioceris quatuordecimpunctata, whose populations in central and eastern Europe inhabit highly geographically isolated areas. All of the studied populations (in Poland, Ukraine, and Slovakia) were differentiated at the mitochondrial marker COI. However, with respect to the nuclear marker ITS1, Polish populations were monomorphic, but distinct from all other populations. The distinctiveness of the studied populations was confirmed by Wolbachia screening, which showed that all populations carried different strains (one or two), which were probably transferred independently from other insects. On the other hand, no diversity was found in any marker within particular populations, which could be caused (at least for mtDNA) by a Wolbachia selective sweep. Crioceris quatuordecimpunctata probably consists of isolated populations, which went through narrow bottlenecks leading to a drastic reduction in their genetic diversity. As these populations are reciprocally monophyletic for mtDNA haplotypes and show a significant divergence of allele frequencies at nuclear loci, they could be classified as evolutionarily significant units (ESUs). In addition, DNA barcodes were used to identify Asparagus officinalis as the host plant for members of all studied populations. These data should be valuable in efforts to conserve populations of C. quatuordecimpunctata (e.g., for guiding reintroductions).     

Partial Sequence Analysis of Geographically Close Grapevine virus A Isolates Reveals their High Regional Variability and an Intra‐Isolate Heterogeneity

To evaluate the genetic diversity of Grapevine virus A (GVA), the genomic region encompassing the partial capsid protein gene and ORF5 was analysed from 10 GVA isolates. Phylogenetic study showed a broad variability of the GVA isolates recovered from a limited geographical area (Slovakia and Czech Republic) and further confirmed the absence of geographical structuration within GVA. Moreover, assessment of structure and intra‐isolate variability revealed that grapevine samples infected with SK13 and SK29 isolates have harboured a population of different sequence variants.     

Comprehensive Research on Essential Oil and Phenolic Variation in Different Foeniculum vulgare Populations During Transition from Vegetative to Reproductive Stage

Chemical composition and antioxidant activity of four fennel populations (England, Spain, Poland and Iran) were investigated during six developmental stages including two vegetative and four reproductive phases. In reproductive phase, the essential oil content of fruits decreased and the maximum content (5.9%) was obtained in immediate fruits. The essential oils were analyzed using GC/MS. trans‐Anethole was the main component of the leaves and the fruits oil. In leaves, it ranged from 41.28% in England at late vegetative stage to 56.6% in Poland population at early vegetative stage. Other major compounds of leaves were limonene, α‐pinene and (Z)‐β‐ocimene. In reproductive phases the trans‐anethole increased dramatically. It varied from 85.25% in immature fruits from Poland to 90.7% in pre‐mature stage from Spain. The highest phenolic content in the extracts at different growth stages obtained 189 mg TAE/g DW at full mature stage of seed in Iran population. The flavonoid of leaves extract ranged from 3 to 7.5 mg QUE/g DW, while in fruits extract varied from 3 to 10.3 mg QUE/g DW. Antioxidant activity of the extracts was evaluated using 1,1‐diphenyl‐2‐picrylhydrazy (DPPH) and β‐carotene model systems. Immature and full mature growth stages of fennel population from Spain indicated the highest activity in quenching of DPPH radical (74.2% and 74.5, respectively). Antioxidant activities of the extracts had high positive correlation with their phenolic contents in all fruit maturity stages. Finally, it might probably be suggested that in fennel the hot and humid condition can lead to increase trans‐anethole, while the hot and dry one can produce higher amount of phenolics and flavonoids.     

Genetic differentiation of southeast Baltic populations of sea trout inferred from single nucleotide polymorphisms

Sea trout (Salmo trutta m. trutta) is a migratory form of brown trout common in the Baltic Sea. Nine populations from the southeast Baltic (Poland; Lithuania; Denmark, Bornholm; Estonia and Russia) were genotyped using iPLEX Gold technology (Sequenom) with 62 informative SNPs. A diagnostic panel of 23 SNPs was applied to estimate genetic differentiation and assess the population structure of Baltic sea trout. The highest level of pairwise F_ST differences was observed between the Russian (East Gulf of Finland) and Polish (Baltic main basin) populations. The lowest differences were between the two Polish and the Polish and Lithuanian populations. A genetic similarity was noted between the Estonian Riguldi River and Danish Bornholm populations, and this finding was supported by a Bayesian and factorial correspondence analysis. Diversity within populations was highest for populations from Estonia and lowest for the Lithuanian population. Genetic structure analysis indicated that individuals from the nine populations were clustered into four groups.     

Genetic diversity of two mitochondrial DNA genes in Spirometra erinaceieuropaei (Cestoda: Diphyllobothridae) from Poland

The tapeworm species Spirometra erinaceieuropaei was documented mainly in Asia and Europe. In recent years, plerocercoid larvae (spargana) of this parasite have been found in different hosts in north‐eastern Poland. The evolutionary history and way of S. erinaceieuropaei spreading across Eurasia have been not described yet. However, this phenomenon could be closely related to the evolutionary history and migration routes of studied tapeworm host species. We investigated the genetic variability and divergence pattern among S. erinaceieuropaei populations in intermediate and paratenic hosts from north‐eastern Poland based on complete mitochondrial sequences of cytochrome b (cytb) and cytochrome c oxidase subunit I (cox1) genes. Analysis of 319 consolidated sequences of these two genes showed no genetic structure across study area. Comparison of sequences from Poland and China showed distinct separation of S. erinaceieuropaei populations from these two regions. They split from their common ancestor approximately 28.6 million years ago. Demographic expansion of Polish population of S. erinaceieuropaei started from glacial refugia approximately 12.5 thousand years ago, and recent population expansion has been observed in the tapeworm population from north‐eastern Poland.