1,720,992 research outputs found
Biocontrol ability of Trichoderma harzianum strain T22 against Fusarium wilt disease on water-stressed lettuce plants
No full textThe control ability of Trichoderma harzianum strain T22 against Fusarium wilt of lettuce caused by Fusarium oxysporum f.sp. lactucae strain 365.07 was studied through mesocosm assays under extreme soil water content available for plants (-0.5 and -0.03 MPa).T22 was applied to nursery substrate at seeding, and to mesocosm soil at transplant of seedlings artficially infected by the pathogen. T22 decreased disease severity in comparison to infected controls by 57 and 78% in dry and wet conditions, respectively. Plant biomass was increased by T22 under both moisture levels. T22 colony growth, spore germination and antagonism to the pathogen were investigated under different water potential ( -0.03, -0.1, -0.5, -1.0, -2.0, -7.0 and -14.0 MPa) on minimal agar medium. All these parameters were influenced by water potential. However, they were similar at the same MPa values tested in the mesocosm assays.Our results provide evidence that T. harzianum strain T22 could be effective to control wilt disease caused by F. oxysporum f.sp. lactucae strain 365.07 under extreme soil moisture regimes already present in Italy, and susceptible to become more frequent in the near future
Viability and infectivity of Tuber borchii after cryopreservation
No full textBACKGROUND: Truffles (Tuber spp.) are the most precious ectomycorrhizal edible mushrooms whose biodiversity is seriously endangered. OBJECTIVE: To develop a protocol for cryopreservation of Tuber spp. mycelia using T. borchii as a model species, verifying whether conservation in liquid nitrogen may affect viability, growth rate, hyphal morphology and infectivity. MATERIALS AND METHODS: Cryopreservation was performed using sorbitol, sucrose and DMSO as cryoprotectants. The morphological parameters analyzed were: hyphal diameter, septal distance and hyphal growth unit. Cryopreserved mycelium infectivity was assessed by inoculating Quercus robur seedlings. RESULTS: In T. borchii cryopreserved mycelium, the lag-phase lasted for 6-42 days but no differences in growth curve evolution, growth rate and hyphal morphology were observed except for hyphal growth unit. No differences in mycorrhizal colonization were observed between the seedlings inoculated with non-cryopreserved and cryopreserved mycelium. CONCLUSION: The established protocol is suitable for long-term conservation of Tuber mycelium and opens up the possibility of creating a Tuber spp. germplasm bank to preserve truffle diversity
Chinese Tuber aestivum sensu lato in Europe
No full textTwo specimens of Tuber aestivum sensu lato from China were found between T. aestivum ascomata for sale in Italy. The morphological features of these ascomata were intermediate between those of T. aestivum and Tuber mesentericum. The spores were roundish and smaller than those of T. mesentericum and T. aestivum. Phylogenetic analyses showed that the Chinese specimens are placed in a separate clade to T. aestivum and T. mesentericum. This, together with the supporting morphological differences, strongly suggests that the two Chinese truffles are a separate taxon
What makes a good truffle infected tree?
No full textModern truffle cultivation is based on planting Tuber infected plants in suitable sites. The first step is the production of truffle infected plants in greenhouses, generally using spore inoculation techniques. Other less common methods include the inoculating plants with pure cultures and the mother plant techniques. Regardless of the inoculation technique used, it is advisable to check the geographic origin of the inoculum, and selecting the most suitable one for the climatic conditions of the site where the plants are to be planted. It is also important to verify the quality of the inoculum before inoculating the plants. In particular, when using spore inoculation techniques, the ascomata used for making the spore suspension should undergo morphological observation and molecular testing to verify the absence of less valuable Tuber species. It is also advisable to assess the abundance of mature spores and their vitality particularly when the inoculum is not produced from fresh truffle. In contrast when mycelial inoculation or mother plant techniques is used it is important to ensure that the plants are carrying two compatible mating types and that the mother plants are free of contamination with other ectomycorrhizal fungi
Ultra-low freezing to preserve the lingzhi or reishi medicinal mushroom Ganoderma lucidum (Agaricomycetes)
No full textGanoderma lucidum (Curtis) P. Karst., commonly used in traditional Chinese medicine, is characterized by strong genetic and phenotypic variability that reflects its active components. To preserve such a source of pharmacologically active metabolites, specimens must be collected from different geographic regions and their genetic integrity ensured during storage. To this aim, we tested the effect of ultra-low freezing (ULF) at −120°C on the vitality, mycelial growth rate, and fruiting ability of 3 Italian strains of G. lucidum. Results showed that all strains reacted positively to ULF, demonstrating an ability to recover after 3 months of storage without morphological or physiological changes occurring, regardless of treatment. The successful storage of G. lucidum at −120°C opens up the possibility to create a germplasm bank to collect strains of this medicinal fungus from throughout Europe, thereby contributing to the maintenance of its diversity
Morphological and molecular characterization of Tuber oligospermum mycorrhizas
No full textTuber oligospermum (Ascomycota) is an edible truffle growing in some Mediterranean countries. In
Morocco, this truffle is regularly harvested and it is exported to Italy. Although T. oligospermum
produces fruiting bodies of good quality, in Italy, it is fraudulently passed off as the most precious
Italian white truffle (Tuber magnatum) and “bianchetto” truffle (Tuber borchii). In this work, a specific
primer able to discriminate T. oligospermum from T. borchii and T. magnatum by multiplex polymerase
chain reaction (PCR) assay was designed and tested for selective amplifications. Moreover, T.
oligospermum ectomycorrhizas were obtained under greenhouse conditions by spore inoculation of
Quercus robur seedlings and their morpho-anatomical characters were described and compared with
those of T. borchii and T. magnatum. The degree of T. oligospermum root colonization was higher than
that obtained for the other 2 truffle species but differences in mycorrhizal morphology were only found
in terms of cystidia type and dimensions. Our results suggest that, T. oligospermum cultivation might
represent an interesting agricultural activity for North African countries
First evidence for truffle production from plants inoculated with mycelial pure cultures
No full textTruffle (Tuber spp.) cultivation is based on raising mycorrhizal trees in greenhouses that have been inoculated with suspensions of ascospores. The problem with this is that pests, pathogens, and other mycorrhizal fungi can contaminate the trees. Furthermore, because ascospores are produced sexually, each plant potentially has a different genetic mycorrhizal makeup from each other so tailoring the mycorrhizal component of plants to suit a particular set of soil and climatic conditions is out of the question. Here, we report on the production of Tuber borchii-mycorrhized plants using pure cultures, establishing a truffià ̈re with these and subsequent production of its fruiting bodies. This study opens up the possibility of producing commercial numbers of Tuber-mycorrhized trees for truffle cultivation using mycelial inoculation techniques. It also poses questions about the mechanism of fertilization between the different strains which were located in different parts of the experimental truffià ̈re
The role of wild boars in spore dispersal of hypogeous fungi
Full text linkWild boars (Sus scrofa L.) are well-known for soil disturbance in natural and cultivated truffières but their role in spore dispersal is poorly investigated. In the present work we studied the occurrence of hypogeous fungal spores in faecal contents of 14 wild boars randomly hunted in “Parco dei Gessi e Calanchi dell’Abbadessa” Regional Park (North of Italy) where truffle production has been previously investigated for three years. Six methods for spore analysis in faeces were compared and the suspension of faeces in ZnSO4 (70%) solution resulted to be the most reliable. Hypogeous fungal spores, including Tuber magnatum and Tuber aestivum spores, were detected in 9 animals. This result suggests that the detection of fungal spores in faeces of wild boars may provide information on the presence of hypogeous fungi in an area. However, the poor abundance of spores suggests that the wild boar can be considered an opportunistic mycophagist, ingesting truffles only occasionally, as a seasonal source of food. Considering the magnitude of wild boar movements during seasonal migrations, it is possible to speculate that they play a key role in truffle long distance dispersal
Techniques for Host Plant Inoculation with Truffles and Other Edible Ectomycorrhizal MushroomsEdible Ectomycorrhizal Mushrooms
No full textLarge-scale production of high-quality mycorrhizal plants in the greenhouse is mainstay for the modern cultivation of edible ectomycorrhizal mushrooms (EEMMs). Success at this step not only depends on the reliability of the fungal inoculum used for plantlet mycorrhization but also on the environmental conditions attending symbiosis establishment. Methods developed 40-50 years ago for inoculating host plants with EEMMs are still largely used today, with slight modifications. Mycelial inoculations are used commercially only for some edible ectomycorrhizal (EEM) basidiomycetes, while inoculation with spores is the most common method for producing seedlings colonized with truffle mycorrhizas. However pure cultures and ectomycorrhizas of Tuber have also been used to obtain mycorrhizal plants mainly for scientific purposes. Mycelium-based inoculum offers many advantages, such as lower contamination risks, more reliable root colonization, and provides opportunities for genetic selection of EEMM strains. Long time preservation of EEM cultures and the creation of germplasm banks would be an important step to support mycelium-based technologies. To this aim, we demonstrate successful crypreservation of strains of Tuber borchii and Tuber aestivum. Recent advances in genetic and biotechnology of EEMs and their hosts has the potential to transform the current EEMM nursery trade
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