Welcome to IMC 2018 International Mycological Congress
Conference Calendar
- M. Neves
- A. Vasco
Mycorrhizal associations of Pseudomonotes tropenbosii (Dipterocarpaceae) in tropical rain forests of Colombia, Amazonia
- A. Vasco-Palacios
- A. Franco-Molano
- T. Boekhout
Abstract
Abstract
Dipterocarpaceae is an important tree family in Paleotropics that form ectomycorrhizal (EcM) symbiosis with fungi and it has been hypothesized that dipterocarps have been partnered in this mutualistic association prior to the separation of Gondwana. Two species of trees have been recently described from Neotropical ecosystems, Pakaraimae dipterocarp from Guyana and Venezuela, and Pseudomonotes tropenbosii from Colombia. We documented the EcM fungal diversity in a terra-firme forest with the endemic dipterocarp Pseudomonotes tropenbosii in the lowlands of Colombian Amazonia by collecting fruit bodies and by using rDNA sequence analysis of root material for identification of both fungal and plant symbionts. We addressed whether the fungal EcM community associated with P. tropenbosii exhibited spatial differences and if the fungal community revealed similar composition that other Neotropical hosts. A total of 83 species of EcM macrofungi were identified based on morphology-based techniques. These taxa represented 16 families and 27 genera. The most abundant families were Boletaceae (7 genera; 13 species), Clavulinaceae and Russulaceae (13 species). Fifteen species constituted new reports for Colombia and at least 18 species found in the study area new to science. Two of those have recently been described as Austroboletus amazonicus, Sarcodon colombiensis and others belong to genera such as Russula, Coltriciella, Coltricia, and Amanita. Species richness detected from 200 fragments of mycorrhizal roots tips revealed 34 species-level (ITS sequences). Seven species were detected three or more times such as Craterellus cinereofimbriatus, Uncultured Cortinarius 866root, Uncultured Tomentella 1452root and Uncultured Sebacina sp. 8. The hosts identified were P. tropenbosii, Coccoloba sp. and other plants not reported as EcM hosts as for example Brosimun, Ipomoea and Protium. Differences were observed in the composition of the EcM fungal community for 3 populations of P. tropenbosii in Colombia Amazonia. Most of the fungal species documented in this study have also been found in symbiotic associations with other legume or dipterocarp species from geographically distant forests located in Brazil, French Guyana, Guyana and Venezuela. The distribution of some fungal species that were previously considered restricted to the Guiana Shield was extended to P. tropenbosii forests in Colombia. The result highlights the low specificity of EcM fungi in relation to their host plants in Neotropical lowland forests. It is important to address further studies in understanding how factor such as forest structure, size of the host plants patches, host distributions and edaphic factors may drive the structure of the EcM fungal communities in Neotropical ecosystems.
African ectomycorrhizal communities, diversity of three vegetation types compared focusing on Russulaceae
- E. De Crop
- T. Semenova
- J. Nuytinck
- J. Geml
- A. Verbeken
Abstract
Abstract
Ectomycorrhizal (ECM) fungi play a major role in tropical and subtropical African forest ecosystems, where many trees, often growing on N- and P-poor soils, completely depend on these associations. Based on above-ground biodiversity records, Russulaceae are the dominant group of ECM fungi in tropical African ecosystems, followed by Boletales and Cantharellaceae. The first soil diversity studies, however, show that Thelephoraceae follow Russulaceae in below-ground species richness. Sub-Saharan Africa is characterized by three vegetation types dominated by ECM associations: Central African Guineo-Congolian rainforests, West African Sudanian woodlands and East African Zambezian Miombo woodlands. Little is known concerning composition and distribution of ECM fungal communities in these vegetation types. We studied ECM fungal diversity of rainforest in Cameroon, Sudanian woodland in Togo and Miombo woodland in Zambia. Root tips were sampled in multiple plots per vegetation type and IonTorrent was used to sequence the ITS2 region from the root tips. Our results confirm Russulaceae as dominant ECM group below-ground in all three vegetation types, followed by Sebacinaceae and Thelephoraceae. ECM fungal community composition is strongly correlated with edaphic factors, with many fungi occurring in either woodland (high pH, together with low C, N and organic material) or rainforest (low pH, together with high C, N and organic material). ECM community composition thus differed amongst the three vegetation types, with the main regions of overlap occurring in the riparian forests in between the vegetation types. It is difficult to draw conclusions on species richness based on metagenomic sequences. Due to the absence of a taxonomical reference framework for most fungal groups, the majority of operational taxonomical units (OTU’s) could only be identified on genus level (>50%) or higher (>15%). This makes it difficult to see trends in species composition between vegetation types. Only for the milkcap genus Lactifluus (Russulaceae), for which we constructed a solid taxonomical framework over the years, most OTU’s could be identified on species level and more detailed conclusions on above- versus below-ground species richness could be drawn.
Ectomycorrhizal fungal communities associated with Oreomunnea mexicana show high beta diversity at local and regional scales in Central America
- A. Corrales
- R. Garibay-Orijel
- C. Alfonso-Corrado
- G. Williams-Linera
- C. Ovrebo
- R. Clark-Tapia
- J. Dalling
- B. Turner
- M. Jusino
- C. Truong
- A. Mujic
- M. Smith
Abstract
Abstract
Oreomunnea mexicana (Juglandaceae) is an ectomycorrhizal (ECM) tree distributed from Mexico to Panama. This species forms monodominant stands in tropical montane forests between 1000 and 1900 m a.s.l. Recent studies of O. mexicana in Panama indicate that this species is associated with a diverse community of ECM fungi, but this tree has been studied at only a few sites. We collected fruiting bodies and root tip samples from eight localities (four in Panama and four in Mexico) to elucidate the effect of geographic location, soil fertility, precipitation, temperature, and host abundance on the ECM fungal communities associated with O. mexicana. Fungal fruiting bodies were preserved and ITS sequences were generated for molecular identification. In addition, ECM roots were sampled from 60 O. mexicana trees (40 trees in Mexico and 20 in Panama) and the fungal communities were assessed based on Illumina ITS1 sequencing. We sequenced 874 ECM fruiting bodies and preliminary results suggest a high a diversity of ectomycorrhizal fungi with approximately 360 OTUs. Of these, 17 OTUs were shared between sites in Mexico and Panama. Fungal diversity in O. mexicana roots based on Illumina sequencing was high, with approximately 4000 OTUs (97% OTUs cutoff and all OTUs > 10 reads) with 1541 belonging to ECM genera. Alpha diversity of both the root-associated fungi and the ECM fungi were higher in Mexico than in Panama, consistent with a previously documented global pattern of decline in species richness of ECM fungi towards the equator. This lower species diversity of ECM fungi in Panama could be associated with a lower species richness and abundance of ECM plant species in the surrounding forests. Beta diversity was high at both regional and local scales with a significant turnover of fungal species. At a local scale, β-diversity was higher in Panamanian O. mexicana populations, with species composition changing rapidly over a short geographical distance. These results are consistent with previous findings based on Sanger sequencing where high β-diversity was found with O. mexicana in sites with contrasting soil fertility. Permutation tests determined that total soil nitrogen was the environmental variable that significantly explained the most variation of both the total root-associated fungal community and the ECM community. However, total soil nitrogen was also highly correlated with total soil carbon (98%). This is the first study to focus on the variation of ECM communities associated with a tropical tree at both regional and subcontinental scales. This work supports the hypothesis that soil nutrient availability is the main factor structuring local ECM fungal communities and that ECM fungal communities are less species rich towards the equator.
Ectomycorrhizae in the Neotropical dry forest: mycobionts, new hosts and morphology
- J. Alvarez Manjarrez
- R. Garibay-Orijel
- A. Solís Rodríguez
Abstract
Abstract
Neotropical dry forest extends from Northern Mexico to Colombia, Brazil, and Peru, also including Caribbean islands. This ecosystem is imperiled by the land use change to agriculture or grazing. Plants and their symbionts from this forest have adaptations to resist long dry periods. Our main objective was to detect the ectomycorrhizal hosts and their mycobionts by sampling roots, fruitbodies and soil, and describe their interactions. We sampled roots from two places from the Mexican Pacific coast, Jalisco and Oaxaca. The roots were dissected and all the ectomycorrhizae (ECM) morphotypes were separated for anatomical observations and sequencing. We also sampled fruitbodies and soil, amplified ITS region, and sequenced by Sanger and Illumina respectively. To identify the photobiont we amplified rbcL, matK and trnL regions from the ECM. We found that ECM were restricted to particular plant genera, such as: Achatocarpus, Coccoloba, Guapira, Pisonia (Caryophyllales), and also some legumes, for example Lonchocarpus. These plants are frequent to scarce in the forest, none of them forms patches. From 19 ectomycorrhizal fungal species we amplified from roots, 18 were not in NCBI or UNITE data bases. ECM fungi belonged to Clavulina, Inocybe, Membranomyces, Russula, Sebacina, Thelephora, Tremelloscypha, Tomentella. We have described three new species including their fruitbodies and mycorrhizal associations: Thelephora versatilis, T. pseudoversatilis and Tomentella brunneoincrustata (Thelephoraceae). Illumina sequences found 121 ectomycorrhizal species as propagules in the soil. Tremelloscypha sp. was the most frequent on root-tips, forming fruit bodies and also in soil sequences. The ECM morphotypes were monopodial and rarely ramified, with a wide range of colors (whitish to dark hyphae), mantle with contact exploration type to mantle with abundant rhizomorphs. Coccoloba, Guapira and Pisonia morphotypes developed a paraepidermal Hartig net, however Achatocarpus does not form Hartig net. Under dry periods, ECM from Coccoloba have incomplete mantles, covering just some parts of the root. Our results showed that ECM fungi are mostly specific, its hosts are scarce in the forest, the ectomycorrhizal fungi are probably endemic, their morphotypes do not present the "typical" ectomycorrhizal characteristics and these vary depending on host and environmental conditions.