Sporulation and germination of spores of Cercospora coffeicola in vitro

A mancha de olho pardo do cafeeiro, cujo agente etiológico é Cercospora coffeicola, é uma das mais antigas e importantes doenças da América Latina. Como a disponibilidade de conídios do patógeno é requerimento básico para vários estudos, é necessário que o fungo esporule abundantemente in vitro. As informações sobre a capacidade de esporulação de Cercospora spp., especificamente C. coffeicola, em meio de cultura, são escassas e contraditórias. Neste trabalho estudaram-se os efeitos de regimes de luz, meios de cultura, pH do meio de cultura e adição de vitaminas na esporulação de C. coffeicola, bem como compararam-se isolados do patógeno quanto à capacidade de esporulação. Adicionalmente, estudou-se a germinação dos conídios do fungo produzidos sob as condições mais propícias à esporulação. Compararam-se cinco meios de cultura, sob três regimes de luz. Os meios V8 (3,55 x 10 3 conídios/cm 2 ) e extrato de pó de café (EPC)+V8 (4,53 x 10 2 conídios/cm 2 ) sob o regime de luz contínua propiciaram melhor esporulação. Os isolados CC-01(4,20 x 10 4 conídios/cm 2 ) e RAP-02 (2,45 x 10 5 conídios/cm 2 ), nos meios V8 e EPC+V8 sob luz contínua, foram os que apresentaram maior capacidade de esporulação. A faixa de pH entre 4,0 e 6,0 não afetou a esporulação dos isolados CC-01 (9,70 x 10 4 conídios/cm 2 ) e RAP-02 (4,56 x 10 4 conídios/cm 2 ), cultivados nos meios V8 e EPC+V8 sob luz contínua. A adição de biotina (50 μg/L), tiamina (100 μg/L) ou Panvit ® (uma drágea/L) aos meios V8 e EPC+V8, não influenciou na esporulação dos isolados CC-01 e RAP-02. A germinação dos conídios em ágar-água 2% foi alta (média geral 97%), independente do isolado (CC-01 ou RAP-02), meio de cultura (V8 ou EPC+V8) ou da fonte de vitamina (tiamina ou Panvit ® ) adicionada ao meio.Brown eye spot, caused by Cercospora coffeicola, it is one of the oldest and most important diseases of coffee plants in Latin America. As the availability of pathogen spores is a requirement to many basic studies, it is necessary to have abundant sporulation of the pathogen in vitro. Information about the sporulation of Cercospora spp., specifically C. coffeicola, in culture media is scarce and contradictory. Therefore this work aimed to study the effect of light regimes, culture media, pH of culture media, and addition of vitamins on sporulation of C. coffeicola. Additionally, sporulation of pathogen isolates was compared and spore germination of the pathogen produced under the most favorable sporulation conditions was studied. Five culture media and three light exposure regimes were compared. V8 (3.55 x 10 3 spores/cm 2 ) and extract of ground coffee (EPC)+V8 (4.53 x 10 2 spores/cm 2 ) media were the most efficient in inducing sporulation, under continuous light. In the two best media, under continuous light, five pathogen isolates were compared. The isolates CC-01 (4.20 x 10 4 spores/cm 2 ) and RAP-02 (2.45 x 10 5 spores/cm 2 ) produced highest number of conidia. In the V8 and EPC+V8 media isolates CC-01 (9.70 x 10 4 spores/cm 2 ) and RAP-02 (4.56 x 10 4 spores/cm 2 ) sporulated well, with no statistical difference, on the medium pH ranging from 4.0 to 6.0. The addition of the vitamins biotin (50 μg/L), thiamin (100 μg/L), or Panvit ® (a capsule/L) to the V8 and EPC+V8 media had no effect on sporulation of CC-01 (1.28 x 10 5 spores/cm 2 ) and RAP-02 (8.41 x 10 3 spores/cm 2 ) isolates. Conidia germination rates high (average 97%), regardless isolate (CC- 01 or RAP-02), culture medium (V8 or EPC+V8), or vitamin source (thiamin or Panvit ® ) added to the medium.Conselho Nacional de Desenvolvimento Científico e TecnológicoDissertação importada do Alexandri

Fungi on some selected aquatic weeds from Brazil and their potential as biocontrol agents

Efetuaram-se levantamentos da micobiota fitopatogênica associada às seguintes plantas aquáticas daninhas no Brasil: Eichhornia crassipes e Eichhornia azurea (Pontederiaceae); Pistia stratiotes (Araceae); Ipomoea carnea (Convolvulaceae); Hymenachne amplexicaulis (Poaceae); Nymphoides indica (Menyanthaceae); Ludwigia spp. (Onagraceae); Hedychium coronarium (Zingiberaceae); Myriophyllum aquaticum (Haloragaceae); Sagittaria montevidensis (Alismataceae); e Typha domingensis (Typhaceae). Dentre estas H. amplexicaulis, N. indica, S. montevidensis, I. carnea e H. coronarium tiveram seus fungos descritos detalhadamente. Com relação às demais plantas, os fungos encontrados foram identificados a nível genérico e quando possível comparado com espécies previamente conhecidas. Estes foram então tabelados de modo a comparar a ocorrência prévia dos mesmos, nestas plantas, no Brasil. Os levantamentos foram conduzidos em todos os estados do sul e sudeste, e também Mato Grosso e Mato Grosso do Sul, visando à busca por potenciais agentes de controle biológico destas importantes invasoras. A seleção dos locais a serem visitados para coleta foi feita com base em registros de ocorrência da plantas em questão em trabalhos publicados, bem como seguindo-se rotas pré-definidas de forma a abranger as principais bacias hidrográficas dessas regiões. Mais de 130 espécies fúngicas distintas foram encontradas associadas às plantas-alvo, sendo que 23 delas foram descritas detalhadamente. Dentre essas quatro novas espécies e uma nova combinação. Além disto, todos os demais fungos coletados e descritos detalhadamente representaram novos registros geográficos para o Brasil ou novo hospedeiro para o taxon.A survey of the pathogenic mycobiota of the following aquatic weeds was undertaken in Brazil: Eichhornia crassipes and Eichhornia azurea (Pontederiaceae); Pistia stratiotes (Araceae); Ipomoea carnea (Convolvulaceae); Hymenachne amplexicaulis (Poaceae); Nymphoides indica (Menyanthaceae); Ludwigia spp. (Onagraceae); Hedychium coronarium (Zingiberaceae); Myriophyllum aquaticum (Haloragaceae); Sagittaria montevidensis (Alismataceae); e Typha domingensis (Typhaceae). Amongst these, H. amplexicaulis, N. indica, S. montevidensis, I. carnea and H. coronarium, had their fungi fully described. This survey was conducted in all states in south and southeastern Brazil as well as in the states of Mato Grosso and Mato Grosso do Sul and the principal aim was the discovery of potential biocontrol agents to be used against these weeds. The site selection was made based on literature and followed pre- determined routes to cover the hydrographic basins of those regions. More than 130 fungal species were found associated with the target-plants. Twenty-three species are fully described and illustrated, being four new species and a new combination. The majority of the others records represent new geographic ranges or new host records.Empresa Brasileira de Pesquisa Agropecuári

Calidion bombacis, a new combination for Uredo bombacis with the record of Bombacopsisglabra (Bombacaceae) as a new host from Brazil

The new combination Calidion bombacis is proposed for the rust species formerly known as Uredobombacis. This nomenclatural change is based on the examination of newly collected material of this fungus from a new host, Bombacopsisglabra from Brazil, and reexamination of the isotype. Until now this fungus was only known to occur in Asia (China, India and Sri Lanka). Therefore, this is also the first record of this fungus from the Neotropics

Bayesian analyses of five gene regions reveal a new phylogenetic species of Macrophomina associated with charcoal rot on oilseed crops in Brazil

Macrophomina is a genus belonging to Botryosphaeriaceae that comprises well-known necrotrophic pathogens related to hundreds of plant hosts around the world. Historically, M. phaseolina is the causal agent of charcoal rot in several crops, mainly in tropical and subtropical areas around the world. However, after a recent genetic diversity study using morphological and molecular approaches, which resulted in the epitypification of M. phaseolina, and the description of a new Macrophomina species associated with charcoal rot disease, the hypothesis that other cryptic species could be present under the name M. phaseolina was raised. Previous studies in Brazil revealed a high genetic diversity and different levels of aggressiveness of M. phaseolina isolates associated with charcoal rot in oilseed crops. Thus, the aim of the present study was, through phylogenetic and morphological studies, to determine if isolates of Macrophomina obtained from different oilseed crops represent a single species or distinct taxa. Based on the results obtained, it was possible to identify three different Macrophomina species: M. phaseolina, M. pseudophaseolina and a new phylogenetic species, M. euphorbiicola. This is first report of M. pseudophaseolina in Brazil causing charcoal rot on Arachis hypogaea, Gossypium hirsutum and Ricinus communis and associated with seed decay of Jatropha curcas. In addition, a novel species described in the present study, M. euphorbiicola, is reported as the etiological agent of the charcoal rot on R. communis and Jatropha gossypifolia

Diversity of Brazilian Fungi

Abstract Knowledge about the Brazilian fungal diversity was, until 2010, recorded in few taxonomy and ecology publications, as well as in a handful of species lists. With the publication of the Catálogo de Plantas e Fungos do Brasil and the continued availability of an online list, it has been possible to aggregate this dispersed knowledge. The version presented here adds 2,111 species names to the 3,608 listed in 2010. A total of 5,719 species of fungi distributed in 1,246 genera, 102 orders and 13 phyla represents a considerable increase over the last five years, when only 924 genera and 78 orders were registered. Basidiomycota (2,741 species in 22 orders) and Ascomycota (1,881 species in 41 orders) predominate over other groups. The Atlantic Rainforest has the largest number of records, with 3,017 species, followed by Amazon Rainforest (1,050), Caatinga (999), Cerrado (638) and Pampa and Pantanal with 84 and 35 species, respectively. The Northeast region has the greatest richness (2,617 species), followed by Southeast (2,252), South (1,995), North (1,301) and Central-West (488 species). Regarding the States of the Federation, São Paulo with 1,846 species, Pernambuco with 1,611 and Rio Grande do Sul with 1,377 species are the most diverse