Untitled

Funder

Organizational Unit

Publications

Effect of competitive interactions between ectomycorrhizal and saprotrophic fungi on Castanea sativa performance

Publication . Pereira, Eric Carvalho; Coelho, Valentim; Tavares, Rui Manuel; Lino-Neto, Teresa; Baptista, Paula

In Northeast of Portugal, the macrofungal community associated to chestnut tree (Castanea sativa Mill.) is rich and diversified. Among fungal species, the ectomycorrhizal Pisolithus tinctorius and the saprotroph Hypholoma fasciculare are common in this habitat. The aim of the present work was to assess the effect of the interaction between both fungi on growth, nutritional status, and physiology of C. sativa seedlings. In pot experiments, C. sativa seedlings were inoculated with P. tinctorius and H. fasciculare individually or in combination. Inoculation with P. tinctorius stimulated the plant growth and resulted in increased foliar-N, foliar-P, and photosynthetic pigment contents. These effects were suppressed when H. fasciculare was simultaneously applied with P. tinctorius. This result could be related to the inhibition of ectomycorrhizal fungus root colonization as a result of antagonism or to the competition for nutrient sources. If chestnut seedlings have been previously inoculated with P. tinctorius, the subsequent inoculation of H. fasciculare 30 days later did not affect root colonization, and mycorrhization benefits were observed. This work confirms an antagonistic interaction between ectomycorrhizal and saprotrophic fungi with consequences on the ectomycorrhizal host physiology. Although P. tinctorius is effective in promoting growth of host trees by establishing mycorrhizae, in the presence of other fungi, it may not always be able to interact with host roots due to an inability to compete with certain fungi.

2012Journal article

Restricted access

A new effective assay to detect antimicrobial activity of filamentous fungi

Publication . Pereira, Eric Carvalho; Santos, A.; Reis, Francisca; Tavares, Rui Manuel; Baptista, Paula; Lino-Neto, Teresa; Almeida-Aguiar, Cristina

The search for new antimicrobial compounds and the optimization of production methods turn the use of antimicrobial susceptibility tests a routine. The most frequently used methods are based on agar diffusion assays or on dilution in agar or broth. For filamentous fungi, the most common antimicrobial activity detection methods comprise the co-culture of two filamentous fungal strains or the use of fungal extracts to test against single-cell microorganisms. Here we report a rapid, effective and reproducible assay to detect fungal antimicrobial activity against single-cell microorganisms. This method allows an easy way of performing a fast antimicrobial screening of actively growing fungi directly against yeast. Because it makes use of an actively growing mycelium, this bioassay also provides a way for studying the production dynamics of antimicrobial compounds by filamentous fungi. The proposed assay is less time consuming and introduces the innovation of allowing the direct detection of fungal antimicrobial properties against single cell microorganisms without the prior isolation of the active substance(s). This is particularly useful when performing large screenings for fungal antimicrobial activity. With this bioassay, antimicrobial activity of Hypholoma fasciculare against yeast species was observed for the first time.

2013Journal article

Restricted access

Soil DNA pyrosequencing and fruitbody surveys reveal contrasting diversity for various fungal ecological guilds in chestnut orchards

Publication . Baptista, Paula; Reis, Francisca; Pereira, Eric Carvalho; Tavares, Rui Manuel; Santos, Pedro M.; Richard, Franck; Selosse, Marc André; Lino-Neto, Teresa

Fungal diversity in Mediterranean forest soils is poorly documented, particularly when considering saprobic and pathogenic organisms. Next-generation sequencing (NGS) methods applied to soil fungi provide the opportunity to unveil the most inconspicuous functional guilds (e.g. saprobes) and life forms (e.g. Corticiaceae) of this tremendous diversity. We used fruitbody surveys over 2 years and soil 454 metabarcoding in Castanea sativa orchards to evaluate res pectively the reproductive (fruitbodies) and vegetative (mycelia) parts of fungal communities in three 100-year-old stands. Analysis of 839 fruitbodies and 210291 ITS1 reads revealed high fungal diversity, mainly shown by belowground analysis, with high (dominant) abundance of mycorrhizal fruitbodies and reads. Both methods displayed contrasted composition and structure of fungal communities, with Basidio- and Ascomycetes dominating above- and belowground, respectively. For the two dominant fungal guilds (i.e. ectomycorrhizal and saprobic), diversity above- and belowground overlapped weakly. This study is the first assessment of the complementarity of fruitbody surveys and NGS for analysing fungal diversity in Mediterranean ecosystems and shows that belowground methods still need to be completed by fruiting diversity to provide a comprehensive overview of the different fungal guilds. The results shed light on chestnut soil biodiversity and question the spatial distribution and synergies among fungal guilds.

2015Journal article

Open access

In vitro interactions between the ectomycorrhizal Pisolithus tinctorius and the saprotroph Hypholoma fasciculare fungi: morphological aspects and volatile production

Publication . Baptista, Paula; Pinho, P. Guedes de; Moreira, Nathalie; Malheiro, Ricardo; Reis, Francisca; Padrão, Jorge; Tavares, Rui Manuel; Lino-Neto, Teresa

Ectomycorrhizal fungi are crucial for forests sustainability. For Castanea sativa, ectomycorrhizal fungus Pisolithus tinctorius is an important mutualist partner. Saprotrophic fungi Hypholoma fasciculare, although used for biocontrol of Armillaria root disease, it negatively affected the interaction between the P. tinctorius and plant host roots, by compromise the formation of P. tinctorius-C. sativa mycorrhizae. In this work, fungal morphology during inhibition of H. fasciculare against P. tinctorius was elucidated. P. tinctorius growth was strongly affected by H. fasciculare, which was significantly reduced after six days of co-culture and become even more significant through time. During this period, P. tinctorius developed vesicles and calcium oxalate crystals, which were described as mechanisms to stress adaption by fungi. H. fasciculare produced different volatile organic compounds in co-cultures over time and differ between single or in dual-species. H. fasciculare highly produced sesquiterpenes (namely, α-muurolene) and nitrogen-containing compounds, which are recognised as having antimicrobial activity.

2021Journal article

Open access

Interaction between Hypholoma fasciculare and the ectomycorrhizal fungus Pisolithus tinctorius

Publication . Baptista, Paula; Pinho, P. Guedes de; Malheiro, Ricardo; Tavares, Rui Manuel; Lino-Neto, Teresa

In the past few years, cord-forming basidiomycetes have received considerable attention in their growth strategies in the presence of other fungi (saprotrophic and pathogenic). In the present study, the in vitro interaction between the cord-forming basidiomycete Hypholoma fasciculare and the ectomycorrhizal fungus Pisolithus tinctorius was studied. Dual-cultures were established and the radial fungal growth, hyphae morphology and production of volatile compounds were evaluated during interaction. Growth of P. tinctorius is severely inhibited by H. fasciculare even before mycelia contact, suggesting a mechanism of antagonism at a distance. Following contact with H. fasciculare mycelia, P. tinctorius displayed distinctive hyphal interference with collapsed or atypical hyphae. Alteration in the production of volatile compounds, distributed in several chemical classes (alcohols, ketones, aldehydes, terpenes, among others) was also detected over the time course of interaction. Sesquiterpenes compounds with putative antifungal properties were the most abundant before fungal contact and their possible role during interaction will be discussed.

2010Conference object

Open access