Surveying potentially antagonistic fungi to myrtle rust (Austropuccinia psidii) in Brazil: fungicolous Cladosporium spp.

The myrtle rust (MR), caused by Austropuccinia psidii, is a worldwide threat to the cultivated and wild Myrtaceae. Originally from the neotropics, it has spread to North America, Africa, and Asia and has reached geographically isolated areas in the Pacific and Australasia. It is attacking native species in those new ranges and is still spreading and causing great concern for the damage caused to endemic Myrtaceae, and to the environment. Classical biological control is regarded as the most sustainable management option for mitigating such biological invasions. However, there are no examples of introductions of host-specific co-evolved natural enemies of plant pathogens, from their native range, as a management strategy for plant pathogens. In order to explore this neglected approach, a survey of potential fungal natural enemies of A. psidii was initiated recently in the state of Minas Gerais (Brazil). Several purported mycoparasites have been collected from A. Psidii pustules formed on myrtaceous hosts. This included some isolates of dematiaceous fungi recognized as having a Cladosporium-like morphology. Here we present the results of the investigation aimed at elucidating their identity through a polyphasic taxonomic approach. Besides morphological and cultural features, molecular analyses using sequences of translation elongation factor 1-α (EF1) and actin (ACT) were performed. The combination of data generated is presented herein and placed all Cladosporium-like isolates in six species of Cladosporium, namely, Cladosporium angulosum, C. anthropophilum, C. bambusicola, C. benschii, C. guizhouense, and C. macadamiae. None of these have ever been recorded in association with A. psidii. Now, with the identification of these isolates at hand, an evaluation of biocontrol potential of these fungi will be initiated. In contrast with the ready finding of fungicolous (possibly mycoparasitic) fungi on MR in this study, no evidence of those was recorded from Australasia until now.

New genus of trichomatous coelomycete on Myrcia fenzliana from the Brazilian Cerrado.

Megacoelomyces (type species: Megacoelomyces sanchezii), an ascomycete asexual morph infecting Myrcia fenzliana (Myrtaceae) from the Brazilian Cerrado, is described as a new genus in the Phaeosphaeriaceae (Pleosporales, Dothideomycetes, Ascomycota), based on multilocus phylogeny (three nuclear ribosomal DNA and two protein-coding genes) in addition to morphological (light and scanning electron microscopy) and ecological data.

Cladosterigma: an enigmatic fungus, previously considered a basidiomycete, now revealed as an ascomycete member of the Gomphillaceae.

Cladosterigma clavariellum has been treated as a basidiomycete since its first description by Spegazzini in 1886 as Microcera clavariella. After further morphological studies, between 1919 and 2011, it remained among the basidiomycetes, most recently as incertae sedis in the order Cryptobasidiales. Our studies, based on light and scanning electron microscopy, supported by multilocus phylogenetic analyses-second-largest subunit of RNA polymerase II (RPB2), translation elongation factor 1-alpha (TEF1), small subunit (18S), large subunit (28S), and nuclear internal transcribed spacers (ITS1-5.8S-ITS2 = ITS) of the nuclear rDNA sequences, and mitochondrial rDNA small subunit (mtSSU)-finally determined the phylogenetic placement of Cladosterigma as the first nonlichenicolous mycoparasitic member of the Gomphillaceae within the Graphidales, an ascomycete order previously composed predominantly of lichen-forming fungi.

Phylogenetic relationships of Phaeochorellaparinarii and recognition of a new family, Phaeochorellaceae (Diaporthales).

Species of Phaeochorella are biotrophic leaf parasites with a tropical distribution, traditionally accepted in the family Phyllachoraceae, Phyllachorales in classifications based on morphological characters. Phylogenetic evidence presented here resolves the relationship of Phaeochorella within the Sordariomycetes, based on a multilocus analysis of partial nuc rDNA large subunit (28S) and internal transcribed spacers (ITS1-5.8S-ITS2 = ITS), the DNA-directed RNA polymerase II second largest subunit (RPB2), and the translation elongation factor 1-α (TEF1-α) gene. Phylogenetic analyses indicate that Phaeochorella belongs to the Diaporthales rather than the Phyllachorales. Phaeochorella parinarii, the type species of the genus, present on native hosts from the Brazilian Cerrado, forms a unique clade with a species of Phaeoappendicospora with high support. Thus, a new family, Phaeochorellaceae, Diaporthales, including both genera, is herein proposed. With the exception of P. parinarii and P. zonata, all other species in Phaeochorella (P. artocarpi, P. ciliata, P. machaerii) were excluded from the genus.

Taxonomy, phylogeny, and divergence time estimation for Apiosphaeria guaranitica, a Neotropical parasite on bignoniaceous hosts.

Apiosphaeria guaranitica, the causal agent of brown crust disease of several bignoniaceous hosts, among them Handroanthus and Tabebuia species, has been traditionally placed in Phyllachoraceae, based exclusively on morphological studies, without supporting molecular evidence. Here, we provide molecular data for the link between sexual and asexual states of the fungus and elucidate the phylogeny of A. guaranitica. The multilocus phylogenetic analyses employed sequences from the 18S subunit (18S), 28S subunit (28S), and nuclear internal transcribed spacers (ITS1-5.8S-ITS2 = ITS) of the nuc rDNA, second-largest subunit of RNA polymerase II (RPB2), and translation elongation factor 1-α (TEF1) genetic loci. Estimates of the divergence time of this lineage were supported by fossil calibration (FC) and secondary calibration (SC) strategies. Our results indicate a natural placement of Apiosphaeria within Diaporthaceae (Diaporthales), where it represents an ancient lineage of the crown group of Diaporthaceae, diverging during the late Paleocene at 61.15 (FC) and 60.63 (SC) million years ago. This divergence time estimate within Diaporthales is based on Spataporthe taylori, a diaporthaceous fossil.