Melissa Faust Bocayuva

Bio: Melissa Faust Bocayuva is an academic researcher from Universidade Federal de Viçosa. The author has contributed to research in topics: Tulasnella & Endangered species. The author has an hindex of 4, co-authored 9 publications receiving 88 citations.

Endophytic and mycorrhizal fungi associated with roots of endangered native orchids from the Atlantic Forest, Brazil.

Abstract: The composition and diversity of fungal commu- nities associated with three endangered orchid species, Hadrolaelia jongheana, Hoffmannseggella caulescens, and Hoffmannseggella cinnabarina, found in different vegeta- tion formations of the Atlantic Forest were determined by constructing clone libraries and by applying diversity and richness indices. Our results demonstrated the presence of Basidiomycetes. Sebacinales (81.61 %) and Cantharellales (12.10 %) were the dominant orders and are potential candi- dates for orchid mycorrhizal fungi. The Ascomycetes iden- tified included the Helotiales (29.31 %), Capnodiales (18.10 %), and Sordariales (10.34 %), among others. These orders may represent potentially endophytic fungi. A Shannon-Wiener diversity index (H') analysis showed a relatively high fungal community diversity associated with these tropical orchids. This diversity may offer greater flex- ibility in terms of the adaptation of the plants to changing environmental conditions and the potential facilitation of reintroduction programs. The Simpson diversity index values showed that all of the libraries included dominant species, and a LIBSHUFF analysis showed that the fungal communities were structurally different from each other, suggesting an influence of local factors on this diversity. This study offers important information for the development of conservation strategies for threatened and endemic species of Brazilian flora in an important and threatened hotspot.

A fine-scale spatial analysis of fungal communities on tropical tree bark unveils the epiphytic rhizosphere in orchids.

Abstract: Approximately 10% of vascular plants are epiphytes and, even though this has long been ignored in past research, are able to interact with a variety of fungi, including mycorrhizal taxa. However, the structure of fungal communities on bark, as well as their relationship with epiphytic plants, is largely unknown. To fill this gap, we conducted environmental metabarcoding of the ITS-2 region to understand the spatial structure of fungal communities of the bark of tropical trees, with a focus on epiphytic orchid mycorrhizal fungi, and tested the influence of root proximity. For all guilds, including orchid mycorrhizal fungi, fungal communities were more similar when spatially close on bark (i.e. they displayed positive spatial autocorrelation). They also showed distance decay of similarity with respect to epiphytic roots, meaning that their composition on bark increasingly differed, compared to roots, with distance from roots. We first showed that all of the investigated fungal guilds exhibited spatial structure at very small scales. This spatial structure was influenced by the roots of epiphytic plants, suggesting the existence of an epiphytic rhizosphere. Finally, we showed that orchid mycorrhizal fungi were aggregated around them, possibly as a result of reciprocal influence between the mycorrhizal partners.

Morphological and molecular characterization of Tulasnella spp. fungi isolated from the roots of Epidendrum secundum , a widespread Brazilian orchid

Abstract: Tulasnella spp. are the main fungal symbionts of Brazilian Epidendrum orchids. The taxonomy of these fungi is largely based on ITS rDNA similarity, but culture dependent techniques are still essential to establish the true biological entity of the mycobiont. The aim of this study was to characterize morphologically and molecularly 16 Tulasnella spp. fungi isolated from three different populations of E. secundum and to test the coincidences between morphological and molecular characterization. Two uninucleate rhizoctonia fungi, obtained from Oncidium barbaceniae, and two phytopathogenic isolates were included as outgroups. Qualitative and quantitative morphological characteristics were analyzed using multivariate statistics and were able to distinguish Ceratobasidium, Tulasnella and Thanatephorus genera and separate the isolates of Tulasnella spp. into two groups. Analysis of RAPD (Random Amplified Polymorphic DNA) and ITS rDNA sequences validated the morphological data. Symbionts of O. barbaceniae presented identity to ITS sequences of Ceratobasidium genus, while E. secundum isolates presented identity to two species of Tulasnella. We observed homogeneity among Tulasnella spp. obtained from a single population and from neighboring populations, but there was higher variability among isolates obtained from populations of regions that were farther apart. Morphological data associated with multivariate statistics proved to be a useful tool in the multi-level taxonomy of these orchid-associated fungi and in estimating the diversity of orchid mycorrhizal fungi.

Diversity of mycorrhizal Tulasnella associated with epiphytic and rupicolous orchids from the Brazilian Atlantic Forest, including four new species.

Abstract: The genus Tulasnella often forms mycorrhizas with orchids and has worldwide distribution. Species of this genus are associated with a wide range of orchids, including endangered hosts. Initially, species identification relied mostly on morphological features and few cultures were preserved for later phylogenetic comparisons. In this study, a total of 50 Tulasnella isolates were collected from their natural sites in Minas Gerais, Brazil, cultured, and subjected to a phylogenetic analysis based on alignments of sequences of the internal transcribed spacer (ITS) of the nuclear ribosomal DNA. Our results, based on phylogeny, integrated with nucleotide divergence and morphology, revealed the diversity of isolated Tulasnella species, which included four new species, namely, Tulasnella brigadeiroensis, Tulasnella hadrolaeliae, Tulasnella orchidis and Tulasnella zygopetali. The conservation of these species is important due to their association with endangered orchid hosts and endemic features in the Brazilian Atlantic Forest.

Sebacinales – one thousand and one interactions with land plants

Abstract: 20 I 21 II 21 III 23 IV 29 V 33 VI 35 36 36 References 36 SUMMARY: Root endophytism and mycorrhizal associations are complex derived traits in fungi that shape plant physiology. Sebacinales (Agaricomycetes, Basidiomycota) display highly diverse interactions with plants. Although early-diverging Sebacinales lineages are root endophytes and/or have saprotrophic abilities, several more derived clades harbour obligate biotrophs forming mycorrhizal associations. Sebacinales thus display transitions from saprotrophy to endophytism and to mycorrhizal nutrition within one fungal order. This review discusses the genomic traits possibly associated with these transitions. We also show how molecular ecology revealed the hyperdiversity of Sebacinales and their evolutionary diversification into two sister families: Sebacinaceae encompasses mainly ectomycorrhizal and early-diverging saprotrophic species; the second family includes endophytes and lineages that repeatedly evolved ericoid, orchid and ectomycorrhizal abilities. We propose the name Serendipitaceae for this family and, within it, we transfer to the genus Serendipita the endophytic cultivable species Piriformospora indica and P. williamsii. Such cultivable Serendipitaceae species provide excellent models for root endophytism, especially because of available genomes, genetic tractability, and broad host plant range including important crop plants and the model plant Arabidopsis thaliana. We review insights gained with endophytic Serendipitaceae species into the molecular mechanisms of endophytism and of beneficial effects on host plants, including enhanced resistance to abiotic and pathogen stress.

Environmental and Microbial Relationships

Abstract: Life History and Genetic Strategies 1 Evolutionary ecology of the first fungi J.H. Andrews and R.F. Harris 2 Molecular approaches for studying fungi in the environment K. Brunner, S. Zeilinger and R.L. Mach Determinants of Fungal Communities 3 Disturbances in natural ecosystems: scaling from fungal diversity to ecosystem functioning S.J. Morris, C.F. Friese, and M.F. Allen 4 Fungal Responses to Disturbance: agriculture and forestry R.M. Miller and D.J. Lodge 5 Fungi and industrial pollutants G.M. Gadd 6 Fungi in extreme environments N. Magan 7 Biogeography and conservation E.J.M. Arnolds Fungal Interactions and Biological Control Strategies 8 Mycoparasitism and antagonism A. Viterbo, J. Inbar, Y. Hadar and I. Chet 9 Antagonism of plant parasitic nematodes by fungi S. Casas-Flores and A. Herrera-Estrella 10 Entomopathogenic Fungi and their role in Pest Control A.K. Charnley and S. A. Collins 11 Bacterial weapons of fungal destruction: Phyllosphere targeted biological control of plant pathogens W. G. Dilantha Fernando, R. Ramarathnam and T. de Kievit 12 Effects of animals grazing on fungi. T. McGonigle 13 Endophytic Fungi P. Bayman 14 Mycorrhizal fungi: their habitats and nutritional strategies M. Girlanda, S. Perotto and P. Bonfante 15 Applications of fungal ecology in the search for new bioactive fungal products J.B. Gloer Decomposition, Biomass and Industrial Applications 16 Nutrient cycling by saprophytic fungi interrestrial habitats J. Dighton 17 Decomposition of plant litter by fungi in marine and freshwater ecosystems M.O. Gessner, V. Gulis, K. Kuehn, E. Chauvet and K. Suberkropp 18 Degradation of cellulose and hemicellulose polymers by fungi C. Gamauf, B. Metz and B. Seiboth

Mixotrophy everywhere on land and in water: the grand écart hypothesis.

Abstract: There is increasing awareness that many terrestrial and aquatic organisms are not strictly heterotrophic or autotrophic but rather mixotrophic. Mixotrophy is an intermediate nutritional strategy, merging autotrophy and heterotrophy to acquire organic carbon and/or other elements, mainly N, P or Fe. We show that both terrestrial and aquatic mixotrophs fall into three categories, namely necrotrophic (where autotrophs prey on other organisms), biotrophic (where heterotrophs gain autotrophy by symbiosis) and absorbotrophic (where autotrophs take up environmental organic molecules). Here we discuss their physiological and ecological relevance since mixotrophy is found in virtually every ecosystem and occurs across the whole eukaryotic phylogeny, suggesting an evolutionary pressure towards mixotrophy. Ecosystem dynamics tend to separate light from non-carbon nutrients (N and P resources): the biological pump and water stratification in aquatic ecosystems deplete non-carbon nutrients from the photic zone, while terrestrial plant successions create a canopy layer with light but devoid of non-carbon soil nutrients. In both aquatic and terrestrial environments organisms face a grand ecart (dancer's splits, i.e., the need to reconcile two opposing needs) between optimal conditions for photosynthesis vs. gain of non-carbon elements. We suggest that mixotrophy allows adaptation of organisms to such ubiquist environmental gradients, ultimately explaining why mixotrophic strategies are widespread.