Response of Tuber melanosporum fruiting to canopy opening in a PinusQuercus forest

[EN] The wild production of the highly appreciated fungus Tuber melanosporum is negatively affected by canopy closure in the stand. Habitat improvement has been proposed as a tool to recover the production in close forests, but evaluations based on scientific monitoring are still lacking. This study analyses the short-term effect of a pilot project on improvement of T. melanosporum reproduction habitat. The results support the project hypothesis that the canopy closure was hampering truffle fruiting in the larger brines. The silvicultural treatment alone has not triggered a clear positive response in all the truffieres, suggesting that complementary actions are necessary to ensure their sustainability. Weather conditions provoke a year-to-year variation in the fruiting and determine the responsiveness of the truffieres to the treatment. (C) 2012 Elsevier B.V. All rights reserved.We gratefully acknowledge the support of the Conselleria de Medi Ambient (Generalitat Valenciana) and VAERSA. CEAM is partly supported by Generalitat Valenciana, Fundacion Bancaja and the projects GRACCIE (Consolider-Ingenio 2010) and FEEDBACKS (Prometeo-Generalitat Valenciana).Garcia Barreda, S.; Reyna Domenech, S. (2013). Response of Tuber melanosporum fruiting to canopy opening in a PinusQuercus forest. Ecological Engineering. 53:54-60. doi:10.1016/j.ecoleng.2012.12.006S54605

Quality assessment of truffle-inoculated seedlings in Italy: proposing revised parameters for certification

Aim of study: the main aims of this study were to evaluate the quality of truffle-inoculated seedlings produced by commercial nurseries in Italy and to identify their minimum requisites in terms of plant age, health, homogeneity, and cut-off percentage of inoculated Tuber and non-Tuber ectomycorrhizae, based on the analysis of an extensive sample of seedlings subjected to quality control and certification.Area of study: truffle-inoculated seedlings produced by Italian commercial nurseries.Material and Methods: analysis of truffle-inoculated seedlings for health and quality standards; recording of presence of inoculated Tuber spp. and other concurrent fungi according to the official Italian method for certification; selective amplification of ectomycorrhizal DNA by PCR species-specific primers.Main results: We showed that mycorrhization levels in truffle-inoculated seedlings increased with time after truffle-spore inoculation. The highest mean percentage of the inoculated Tuber spp., but also the highest presence of contaminants, were recorded after three years. The mycorrhization level of Tuber melanosporum and T. aestivum was higher in Corylus and Ostrya seedlings than in Q. ilex and Q. pubescens, but the latter two host species showed the lowest presence of other ectomycorrhizal fungi. Mycorrhization level distribution in truffle-inoculated seedlings of suitable batches differed very little from the distribution in only all suitable seedlings. Truffle seedlings with other Tuber spp. were very few and even absent after three years. The general quality of Italian truffle-inoculated seedlings is high but can be improved even further by revising the parameters used for their certification.Research highlights: Mycorrhization assessment in truffle-inoculated seedlings produced by commercial nurseries and a revision of the parameters of quality standards following several years of certification in Italy.Keywords: Truffle cultivation; truffle seedlings; mycorrhization level; Tuber; commercial nursery; certification methods.</p

Selection of a set of specific primers for the identification of Tuber rufum: a truffle species of high genetic variability

Tuber rufum is a truffle widely distributed throughout Europe, which forms mycorrhizal associations with numerous species of broadleaf and coniferous trees. The possibility of T. rufum contamination in commercial truffle-infected plants makes its detection important. To facilitate the identification of T. rufum from mycorrhiza and fruitbodies, species-specific primers were designed and tested. To overcome the high intraspecific genetic variability within the internal transcribed spacer (ITS) regions of T. rufum, as demonstrated by phylogenetic analysis, two forward primers, Ru1f and Ru2f, located on the ITS1 region were designed to be used in concert with the reverse primer ITS4. Only T. rufum was amplified with this primer combination, while DNA of Tuber magnatum, Tuber brumale, Tuber maculatum, Tuber borchii, Tuber excavatum and Tuber melanosporum was not. These primers give a specific amplicon ranging between 566 and 572 bp and are able to discriminate between T. rufum, T. borchii and T. magnatum in multiplex PCR. In addition, T. rufum-specific amplicons were obtained from both spore suspensions and mycorrhiza by direct PCR. Tuber rufum mycorrhiza obtained in the greenhouse using mycelial inoculation techniques had morphological features similar to those of other species of Tuber, stressing the importance of molecular tools for their identification