José C. Dianese

Unusual fungal niches

Fungi are found in all aerobic ecosystems, colonizing a diversity of substrates and performing a wide diversity of functions, some of which are not well understood. Many species of fungi are cosmopolitan and generalists but others are specialists found only in restricted substrates or habitats. Unusual fungal niches are habitats where extreme conditions would be expected to prevent the development of a mycobiota. In this review we describe five unusual fungal habitats in which fungi occupy poorly understood niches: Antarctic dry valleys, high Arctic glaciers, salt flats and salterns, hypersaline microbial mats and plant trichomes. Yeasts, black yeast-like fungi, melanized filamentous species as well as representatives of Aspergillus and Penicillium seem to be dominant among the mycobiota adapted to cold and saline niches. Plant trichomes appear to be a unique niche, harboring many previously unknown taxa. The advent of new sequencing technologies is helping to elucidate the microbial diversity in many ecosystems, but more studies are needed to document the functional role of fungi in the microbial communities thriving in these unusual environments.

Grape rust caused by Phakopsora euvitis, a new disease for Brazil

A ferrugem da videira foi constatada pela primeira vez no Brasil, ocorrendo em parreirais (Vitis spp.)comerciais no estado do Parana tendo recentemente atingido tambem o Estado de Sao Paulo. O fungo Phakopsora euvitis foi identificado como o agente causal da doenca. Esta ferrugem ocorre preferencialmente em folhas maduras causando a desfolha precoce das plantas infetadas.

Hentriacontane: a leaf hydrocarbon from Syzygium jambos with stimulatory effects on the germination of urediniospores of Puccinia psidii

A crude Sohxlet extract from leaves of Syzygium jambos was sequentially fractionated using a silica gel flash column. A bioassay based on the numbers of urediniospores of Puccinia psidii that germinated in 2% water agar detected an active stimulant of germination when the fraction eluted with 100% n-hexane was used. The active fraction induced up to 88% increase in germination when added to a spore suspension in mineral oil. The active fraction was characterized as a hydrocarbon by 1H nuclear magnetic resonance, 13C nuclear magnetic resonance, and infrared analysis. Gas chromatography-mass spectrometry analysis indicated that the fraction was a long-chain 436 MW hydrocarbon with corresponding to C31H64, namely hentriacontane. This is the first time such a compound proved to be involved with stimulation of fungal spore germination. These results may contribute to better understanding the infection process of rusts.

Padrões de liberação de urediniósporos e desenvolvimento da ferrugem do jambeiro

Patterns of urediniospores release and development of rose apple rust Abstract†n†This research was conducted to evaluate some epidemiological features of the rose apple (Syzygium jambos) rust (Puccinia psidii Winter) under field conditions at the Universidade de BrasIlia, BrasIlia, DF, Brazil, from March 29 through December 31, 1988. Data for the amount of airborne urediniospores were collected in ten plants, using a Burkardis seven-day volumetric spore trap set between two rose apple trees. Most of the airborne urediniospores were collected between June 23 and July 6, from 10†a.m. to 1†p.m. The†major quantity of S.†jambos affected shoots occurred between April 28 and July 20. There was a positive correlation between the amount of trapped urediniospores and infected young shoots. A†negative correlation was shown between temperature (12h) and number of airborne urediniospores. The number of days with relative humidity (RH)†‡80% was positively corre- lated to the amount of deformed shoots. Also, the amount of urediniospores and infected young shoots were positively correlated to the number of days with night (24h) temperature £20 o C or night RH‡80%. These data show that this disease was favored by low temperatures (£20 o C), high night RH†(‡80%) and high levels of airborne urediniospores.

Hyphomycetes on the Vochysiaceae from the Brazilian cerrado.

New hyphomycetes are described in association with leaves of native plants of the family Vochysiaceae, as part of studies of cerrado fungi. Six new species are described belonging to genera Alternaria (A. qualeae sp. nov.), Janetia (J. salvertiae sp. nov.), Passalora (P. qualeae sp. nov.) and Periconiella (P. longispora sp. nov., P. qualeae-grandiflorae sp. nov. and P. campo-grandensis sp. nov.). A key to the species of Periconiella on Qualea is provided.

An overlooked source of fungal diversity: novel hyphomycete genera on trichomes of cerrado plants.

Eight monotypic hyphomycete genera new to science are described from the trichomes of native plants growing in the cerrado of Brazil: Trichomatoclava cerradensis, Echinoconidiophorum cerradense, Globoconidiopsis cerradensis, Globoconidium cerradense, Helminthosporiomyces cerradensis, Trichomatosphaera [corrected] cerradensis , Phragmoconidium cerradense, and Vesiculohyphomyces cerradensis gens. spp. nov. Two of the new genera were found on hosts belonging in Myrtaceae, and one of each of the following families: Icacinaceae, Malphigiaceae, Fabaceae, Dilleniaceae, Chrysobalanaceae, and Caryocaraceae. These discoveries suggest that the trichomes of neotropical plants are an unexplored source of novel fungal diversity, and merit more attention in biodiversity surveys.

New hyphomycete genera on Qualea species from the Brazilian cerrado

As part of studies on cerrado fungi three new hyphomycetes are described in association with trichomes on leaves of native species of Qualea (Vochysiaceae). These are: Trichomatomyces gen. nov. (type species: T. byrsonimae comb. nov.), Trichosporodochium gen. nov. (type species: T. cerradensis sp. nov.), and Phaeoidiomyces gen. nov. (type species: P. qualeae).

Some coelomycetes from Central Brazil.

As part of an inventory of mycodiversity in the Brazilian Cerrado new coelomycetes were collected and are herein described: Phyllosticta xylopiae-sericeae sp. nov., Dinemasporium duguetiae sp. nov., Harknessia salvertiana sp. nov., Harknessia qualeae sp. nov. on living leaves of Xylopia sericea, Duguetia furfuracea, Salvertia convallariodora, and Qualea grandiflora, respectively. Pseudothiopsella hirtellae is reported on a new host, Hirtella gracilipes, and for the first time illustrated in detail.

Some Pseudocercospora species and a new Prathigada species from the Brazilian cerrado

Pseudocercospora bolkanii sp. nov., and P. luzardii sp. nov., were collected in the Brazilian cerrado on leaves of Strychnos pseudoquina , and Hancornia speciosa , respectively. Prathigada backmanii sp. nov., is described on leaf spots of Bowdichia virgilioides. Pseudocercospora curatellae on Curatella americana is illustrated in detail.

New cercosporoid fungi from the Brazilian Cerrado 2. Species on hosts of the subfamilies Caesalpinioideae, Faboideae and Mimosoideae (Leguminosae s. lat.)

The genus Passalora is divided into the morphological sections Passalora, Phaeoramularia, Mycovellosiella and Pseudophaeoisariopsis. New cercosporoid hyphomycetes are described from the Brazilian Cerrado on native plants of the subfamilies Mimosaoideae (Cercospora mimosae-sensitivae), Faboideae (Passalora sect. Mycovellosiella: P. acosmii), and Caesalpinioideae (Passalora sect. Mycovellosiella: P. chamaecristae-orbiculatae; Passalora sect. Passalora: P. chamaecristicola, P. machaerii; Pseudocercospora: P. exilis, P. chamaecristigena, and P. luzianiensis). Furthermore, the new combinations Passalora caesalpiniae (≡ Phaeoramularia caesalpiniae), P. dalbergiae (≡ Mycovellosiella dalbergiae), Pseudocercospora bonducellae (≡ Helminthosporium bonducellae) and the new name Pseudocercospora caesalpiniicola (≡ Phaeoisariopsis caesalpiniae, non Pseudocercospora caesalpiniae) are introduced.