Marie-France Roquebert

Phaeoacremonium viticola, a new species associated with Esca disease of grapevine in France

A group of Phaeoacremonium isolates first distinguished by the red pigmentation of the reverse of their colonies, is described as a new species, P. viticola, on the basis of molecular data. An intensive sampling in French vineyards affected by the Esca disease has shown that this species is rare compared to P. aleophilum and P chlamydosporum and is often associated with symptoms on the fruits.

Biodegradation potential of hydrocarbon-assimilating tropical fungi

Abstract Strains of hydrocarbon-degrading fungi were isolated from tropical polluted environments in Indonesia: a forest soil and the sediments of a river which had been contaminated by petroleum spills. The biodegradation potential of these isolates was monitored by measuring the degradation rate of total petroleum, saturated hydrocarbons, aromatic hydrocarbons, resins and asphaltenes. Members of the genera Aspergillus, Penicillium, Gliocladium, Emericella, Graphium, Acremonium, Eupenicilium and Talaromyces were identified. The most active strains in the assimilation of saturates and aromatics were Emericella nidulans, Graphiwn putredinis, Eupenicillium javanicum and Aspergillus flavipes . Some isolates degraded significantly the resins and asphaltenes. Monospecific cultures were as efficient as mixed cultures. The degradative capacities were not constant within a species and this metabolic activity cannot be used in taxonomic studies.

Feeding preferences of the collembolan Onychiurus sinensis for fungi colonizing holm oak litter (Quercus rotundifolia Lam.)

Abstract Ten fungi isolated from decaying holm oak leaves ( Quercus rotundifolia Lam.) have been presented to the collembolan species Onychiurus sinensis (Hexapoda). The attractiveness and selectivity of the ten fungi was investigated taken into account the effect of the substrate on which the fungus was growing (malt-agar or litter) and the effect of fungal odour. Furthermore, moulting, growth, survival and reproduction of O. sinensis in the presence of each of the ten test fungi were studied. Mucor plumbeus and Trichothecium roseum were the most preferred whatever the culture substrate and their odour was the most attractive. Two fungi ( Penicillium spinulosum and the Basidiomycete S41) attracted Collembola by their odour but were not preferred as food sources. The animals could survive and reproduce on a mono-diet of several of our test fungi, but not on the Basidiomycete S41 and on Trichoderma polysporum .

Partial ribosomal DNA sequences show an important divergence between Phaeoacremonium species isolated from Vitis vinifera

A morphological and molecular analysis was performed on 25 individuals of Phaeoacremonium isolated from diseased European and Californian grapevines (Esca disease). An unexpectedly high intra-generic molecular divergence was evidenced by partial rDNA sequencing between P. chlamydosporum isolates on one hand and an aggregate including P. angustius and P. aleophilum isolates and some undescribed ones on the other. These two groups show 26% nucleotide differences within the 26S rDNA fragment sequenced and were unalignable within the ITS2, suggesting distant phylogenetic relationships. Moreover, P. chlamydosporum appeared more closely related to Phialophora verrucosa (supposed to be an anamorph of the Herpotrichiellacae), than to the type species of the genus, P. parasiticum (more related to Magnaporthaceae).

The Genus "Phaeoacremonium" from a Molecular Point of View

A molecular approach combined with phenotypic and morphological observations was used to delimit Phaeoacremonium species involved in esca disease and grapevine declines. P. aleophilum and P. angustius were synonymised, a new species P. viticola was reported and preliminary results concerning the delimitation of P. inflatipes and P. parasiticum were presented. The incubation of isolates at 35°C appeared to be a discriminant character to identify these two species, P. inflatipes having very low growth in comparison with P. parasiticum. Specific restriction profiles were determined using the type strain of each species, and the method was applied to screen unidentified isolates.

PCR-RFLP of ITS rDNA for the rapid identification of Penicillium subgenus Biverticillium species.

RFLP of ITS rDNA is proposed as a useful tool for molecular identification of the most common species of biverticillate penicillia. 60 isolates were analysed representing 13 species and 21 unique sequences were produced. The combination of five restriction enzymes was successful in separating 12 species. However, the variety Penicillium purpurogenum var. rubrisclerotium remained indistinguishable from Penicillium funiculosum. P. funiculosum appeared as the most confused species, being mis-identified with Penicillium miniolutum and Penicillium pinophilum, which were originally part of the species, and with P. purpurogenum perhaps because of the common production of red pigment. Penicillium variabile was difficult to investigate as introns were found on half of the isolates. Penicillium piceum, Penicillium rugulosum, Penicillium loliense, Penicillium erythromellis and P. purpurogenum were homogeneous from molecular and morphological positions and corresponded to a well circumscribed taxon. Furthermore, intraspecific variability was evidenced within P. pinophilum and P. funiculosum. The ex-type isolate of P. funiculosum produced a unique pattern. The method is sensitive, rapid and inexpensive and can be used for isolate identification of the biverticillate species. It is recommended particularly when many isolates have to be authentificated prior to analysis for phylogenetic assessment or population genetics.

Paraná river delta wetlands soil microfungi

Summary The Parana River Delta soils are affected by seasonal flooding coupled with rapidly flowing water from the Parana River and by the de la Plata River estuary tidal regime which reduces the seasonality of the Parana River regime. The present study is the first investigation undertaken to determine the fungal composition of different site soils and to evaluate if flooding and flowing water energy induced differences on fungal community. Five sites were selected and three plots at each site along a topographical gradient were examined. From all soil samples, 23041 isolates belonging to 74 taxa were obtained. Talaromyces flavus and Eupenicillium brefeldianum were the most frequent species and present with high densities. Several taxa were soil or site specific. A black yeast, Pseudeurotium zonatum, Phialemonium dimorphosporum, Eladia saccula, Phialophara spp., Aspergillus japonicus, Eupenicillium abidjanum, Arachnotheca albicans, Fusarium oxysporum and Westerdykella spp. also were common. Correspondence analysis evidenced differences among sites characterized by a set of several species. The distribution of these species shows little or no relationship with the overlying vegetation. The low microfungal biomass, the high number of taxa by 100 isolates, and the mainly dematiaceous and cleistothecial forms suggest that these soil fungal communities are disturbed. Differences among fungal communities at each site could reflect difterent disturbance conditions derived from the effect of flooding and flowing water at the Upper, Medium and Lower Parana River Delta as well as the Rio de la Plata estuary tidal regime.