What is Johansonia?

The bitunicate ascomycete genus Johansonia is presently treated as a member of Saccardiaceae, a family regarded as incertae sedis within the Ascomycota. Recent collections on leaves of a leguminous host, Dimorphandra mollis, in Mato Grosso, Brazil, led to the discovery of a new species of Johansonia, described here as J. chapadiensis. Based on DNA sequence data of the nuclear ribosomal DNA (LSU), Johansonia is revealed to represent a member of Dothideomycetes, Capnodiales. Although its family could not be resolved, it clustered basal to Schizothyriaceae and Mycosphaerellaceae, and could well represent a species of Saccardiaceae. DNA sequence data of other members of Saccardiaceae would be required, however, to confirm this classification

Mycoparasitic species of Sphaerellopsis, and allied lichenicolous and other genera

Species of Sphaerellopsis (sexual morph Eudarluca) are well-known cosmopolitan mycoparasites occurring on a wide range of rusts. Although their potential role as biocontrol agents has received some attention, the molecular phylogeny of the genus has never been resolved. Based on morphology and DNA sequence data of the large subunit nuclear ribosomal RNA gene (LSU, 28S) and the internal transcribed spacers (ITS) and 5.8S rRNA gene of the nrDNA operon, the genus Sphaerellopsis is shown to belong to Leptosphaeriaceae in Dothideomycetes. Sphaerellopsis is circumscribed, and the sexually typified generic name Eudarluca treated as a synonym on the basis that Sphaerellopsis is more commonly used in literature, is the older generic name, and is the morph commonly encountered by plant pathologists in the field. A neotype is designated for Sphaerellopsis filum, and two new species are introduced, S. macroconidialis and S. paraphysata spp. nov. Species previously incorrectly placed in Sphaerellopsis are allocated to Neosphaerellopsis gen. nov. as N. thailandica, and to the genus Acrocalymma, as A. fici. The genus Rhizopycnis is nestled among species of Acrocalymma, and reduced to synonymy based on its morphology and DNA phylogeny, while Acrocalymmaceae is introduced as novel family to accommodate members of this genus in the Dothideomycetes. Furthermore, Sphaerellopsis proved to be phylogenetically closely allied to a lichenicolous complex of phoma-like taxa, for which the new genera Diederichomyces and Xenophoma are established. Several new combinations are introduced, namely D. xanthomendozae, D. ficuzzae, D. caloplacae, D. cladoniicola, D. foliaceiphila, and X. puncteliae combs. nov, while Paraphaeosphaeria parmeliae sp. nov. is newly described

Reação de clones de seringueira a vários isolados de Microcyclus ulei

The reactions of 33 clones of Hevea to various M. ulei isolates collected from rubber plantations in different regions of Brazil were studied. Isolates were inoculated with a concentration of 2 x 105 conidia/ml with 70% - 80% of germination rate. The subculturing was made with a 12-day old culture macerated in distilled sterilized water. The reaction presented by clones of Hevea spp varied with isolates and with clones. Most of the clones showed complete resistance to some of the isolates, but the same clones were susceptible or highly susceptible to the others. Some clones showed complete resistance and varying levels of incomplete resistance. It was verified that both the latent period and the diameter of lesions may be related to rubber tree resistance to M. ulei, but these two parameters are not sufficient to explain this resistance. The association of various resistance components is needed. Among these components, the "sporulation on the lesions" is the most important. The incubation period and number of lesions are not good parameters for analyzing the rubber tree resistance to M. ulei. Estudou-se a reação de 33 clones de seringueira à infecção por vários isolados de Microcyclus ulei, provenientes de várias regiões heveícolas do Brasil. As inoculações foram feitas em condições climáticas controladas, utilizando-se 2 x 105 conídios/ml com 70% a 80% de germinação, provenientes de culturas com doze dias de idade. As reações apresentadas pelos clones variaram com os isolados. Os clones, em sua maioria, apresentaram resistência completa a determinados isolados e foram suscetíveis ou altamente suscetíveis a outros. Alguns clones apresentaram resistência completa a alguns isolados e incompleta a outros, mas em níveis variados. Verificou-se que o período latente e o diâmetro médio das lesões podem estar relacionados com a resistência dos clones de seringueira ao M. ulei, mas somente estes parâmetros não explicam essa resistência, sendo necessária a associação de vários componentes, dentre os quais o mais importante é a esporulação do tecido infectado. O período de incubação e o número de lesões não são bons parâmetros para análise da resistência da seringueira ao M. ulei

Phylogenetic reassessment of Mycosphaerella spp. and their anamorphs occurring on Eucalyptus. II.

Species of Eucalyptus are widely planted as exotics in the tropics and Southern Hemisphere and to some extent in southern Europe, for timber and fibre production. Species of Mycosphaerella are commonly associated with leaves and twigs of Eucalyptus and can result in defoliation, dieback, and even tree death. In the present study, numerous isolates of Mycosphaerella species were collected from leaf litter, living leaves exhibiting leaf spot symptoms or severe Mycosphaerella leaf blotch symptoms. Isolates were compared based on DNA sequence data for the internal transcribed spacer region (ITS1 & ITS2) and the 5.8S gene. These data, together with characteristics of the fungal growth on three different media, morphology of the anamorph and teleomorph structures as well as ascospore germination patterns were used to describe 21 new species