Eucalyptus microfungi known from culture. 1. Cladoriella and Fulvoflamma genera nova, with notes on some other poorly known taxa

A study of microfungi associated with living Eucalyptus leaves and leaf litter revealed several novel and interesting taxa. Cladoriella eucalypti gen. et sp. nov. is described as a Cladosporium-like genus associated with litter collected in South Africa, while Fulvoflamma eucalypti gen. et. sp. nov. is newly described from leaf litter collected in Spain. Beta-conidia are newly reported for species of Pestalotiopsis, namely Pestalotiopsis disseminata in New Zealand, and a Pestalotiopsis sp. from Colombia. Satchmopsis brasiliensis is reported from litter in Colombia and Indonesia, while Torrendiella eucalypti is reported from leaf litter in Indonesia, and shown to have a Sporothrix-like anamorph. Leptospora rubella is reported from living Eucalyptus leaves in Colombia, where it is associated with leaf spots of Mycosphaerella longibasalis, while Macrohilum eucalypti is reported from leaf spots of Eucalyptus in New Zealand

Species of Cercospora associated with grey leaf spot of maize

Grey leaf spot is a serious yield-reducing disease of maize (Zea mays) in many parts of the world where this crop is cultivated. The causal organism associated with the disease is Cercospora zeae-maydis. Two potential sibling species have been recognized as Groups I and II. The DNA sequences for the internal transcribed spacers (ITS1 & ITS2), the 5.8S rRNA gene, elongation factor 1-α, histone H3, actin and calmodulin gene regions suggest that Groups I and II are two distinct species. Furthermore, Cercospora zeae-maydis (Group I) can be distinguished from C. zeina sp. nov. (Group II) by its faster growth rate on artificial media, the ability to produce cercosporin, longer conidiophores, and broadly fusiform conidia. A PCR-based test that distinguishes the two species was developed using species-specific primers designed from the histone H3 gene

Re-evaluating the taxonomic status of Phaeoisariopsis griseola, the causal agent of angular leaf spot of bean

Angular leaf spot of Phaseolus vulgaris is a serious disease caused by Phaeoisariopsis griseola, in which two major gene pools occur, namely Andean and Middle-American. Sequence analysis of the SSU region of nrDNA revealed the genus Phaeoisariopsis to be indistinguishable from other hyphomycete anamorph genera associated with Mycosphaerella, namely Pseudocercospora and Stigmina. A new combination is therefore proposed in the genus Pseudocercospora, a name to be conserved over Phaeoisariopsis and Stigmina. Further comparisons by means of morphology, cultural characteristics, and DNA sequence analysis of the ITS, calmodulin, and actin gene regions delineated two groups within P. griseola, which are recognised as two formae, namely f. griseola and f. mesoamericana

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

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

Characterisation of Phomopsis spp. associated with die-back of rooibos (Aspalathus linearis) in South Africa

Die-back of rooibos (Aspalathus linearis) causes substantial losses in commercial Aspalathus plantations in South Africa. In the past, the disease has been attributed to Phomopsis phaseoli (teleomorph: Diaporthe phaseolorum). Isolates obtained from diseased plants, however, were highly variable with regard to morphology and pathogenicity. The aim of the present study was thus to identify the Phomopsis species associated with die-back of rooibos. Isolates were subjected to DNA sequence comparisons of the internal transcribed spacer region (ITS1, 5.8S, ITS2) and partial sequences of the translation elongation factor-1 alpha gene. Furthermore, isolates were also compared in glasshouse inoculation trials on 8-mo-old potted plants to evaluate their pathogenicity. Five species were identified, of which D. aspalathi (formerly identified as D. phaseolorum or D. phaseolorum var. meridionalis) proved to be the most virulent, followed by D. ambigua, Phomopsis theicola, one species of Libertella and Phomopsis, respectively, and a newly described species, P. cuppatea. A description is also provided for D. ambigua based on a newly designated epitype specimen

Genetic diversity in Macrophomina phaseolina, the causal agent of charcoal rot

Macrophomina phaseolina (Botryosphaeriaceae) is an important soil- and seed-borne pathogen. This pathogen has a broad geographic distribution, and a large host range. The aim of the present study was to determine the genetic variation among a global set of 189 isolates of M. phaseolina, isolated from 23 hosts and 30 soil samples in 15 countries. To achieve this goal a multi-gene DNA analysis was conducted for the following five loci, ITS, TEF, ACT, CAL and TUB. Based on these results two well-defined clusters could be delineated, one corresponding to M. phaseolina s. str., for which a suitable epitype is designated. The second clade corresponds to M. pseudophaseolina, a novel species occurring on Abelmoschus esculentus, Arachis hypogaea, Hibiscus sabdarifa and Vigna unguiculata in Senegal. No consistent correlation was found among genotype, host and geographic location, and both species could even occur on the same host at the same location. Although M. pseudophaseolina is presently only known from Senegal, further research is required to determine its virulence compared to M. phaseolina, and its geographic distribution

Phyllosticta citricarpa and sister species of global importance to Citrus.

Several Phyllosticta species are known as pathogens of Citrus spp., and are responsible for various disease symptoms including leaf and fruit spots. One of the most important species is P. citricarpa, which causes a foliar and fruit disease called citrus black spot. The Phyllosticta species occurring on citrus can most effectively be distinguished from P. citricarpa by means of multilocus DNA sequence data. Recent studies also demonstrated P. citricarpa to be heterothallic, and reported successful mating in the laboratory. Since the domestication of citrus, different clones of P. citricarpa have escaped Asia to other continents via trade routes, with obvious disease management consequences. This pathogen profile represents a comprehensive literature review of this pathogen and allied taxa associated with citrus, focusing on identification, distribution, genomics, epidemiology and disease management. This review also considers the knowledge emerging from seven genomes of Phyllosticta spp., demonstrating unknown aspects of these species, including their mating behaviour.TaxonomyPhyllosticta citricarpa (McAlpine) Aa, 1973. Kingdom Fungi, Phylum Ascomycota, Class Dothideomycetes, Order Botryosphaeriales, Family Phyllostictaceae, Genus Phyllosticta, Species citricarpa.Host rangeConfirmed on more than 12 Citrus species, Phyllosticta citricarpa has only been found on plant species in the Rutaceae.Disease symptomsP. citricarpa causes diverse symptoms such as hard spot, virulent spot, false melanose and freckle spot on fruit, and necrotic lesions on leaves and twigs.Useful websitesDOE Joint Genome Institute MycoCosm portals for the Phyllosticta capitalensis (https://genome.jgi.doe.gov/Phycap1), P. citriasiana (https://genome.jgi.doe.gov/Phycit1), P. citribraziliensis (https://genome.jgi.doe.gov/Phcit1), P. citrichinaensis (https://genome.jgi.doe.gov/Phcitr1), P. citricarpa (https://genome.jgi.doe.gov/Phycitr1, https://genome.jgi.doe.gov/Phycpc1), P. paracitricarpa (https://genome.jgi.doe.gov/Phy27169) genomes. All available Phyllosticta genomes on MycoCosm can be viewed at https://genome.jgi.doe.gov/Phyllosticta

Lineages in Nectriaceae: re-evaluating the generic status of Ilyonectria and allied genera

Genera with cylindrocarpon-like asexual morphs are important pathogens of various herbaceous and woody plant hosts globally. Recent multi-gene studies of this generic complex indicated that the genus Ilyonectria is paraphyletic. The present study was therefore initiated to re-evaluate the generic status of Ilyonectria and at the same time address some taxonomic irregularities in the genera Cylindrodendrum and Neonectria. Using multi-gene DNA data and morphological comparisons, the genus Dactylonectria is introduced with 10 new combinations, several of which were previously treated in Ilyonectria. Two new species, D. hordeicola and D. pinicola, are also described. Furthermore, one new combination is provided in the genus Cylindrodendrum, and three new combinations in the genus Neonectria, for species previously treated in the genera Acremonium, Cylindrocarpon, Nectria and Neonectria. The aquatic genus Heliscus is reduced to synonymy under Neonectria.

Diversity and movement of indoor Alternaria alternata across the mainland USA

Alternaria spp. from sect. Alternaria are frequently associated with hypersensitivity pneumonitis, asthma and allergic fungal rhinitis and sinusitis. Since Alternaria is omnipresent in the outdoor environment, it is thought that the indoor spore concentration is mainly influenced by the outdoor spore concentration. However, few studies have investigated indoor Alternaria isolates, or attempted a phylogeographic or population genetic approach to investigate their movement. Therefore, the aim of the current study was to investigate the molecular diversity of indoor Alternaria isolates in the USA, and to test for recombination, using these approaches. Alternaria isolates collected throughout the USA were identified using ITS, gapdh and endoPG gene sequencing. This was followed by genotyping and population genetic inference of isolates belonging to Alternaria sect. Alternaria together with 37 reference isolates, using five microsatellite markers. Phylogenetic analyses revealed that species of Alternaria sect. Alternaria represented 98% (153 isolates) of the indoor isolates collected throughout the USA, of which 137 isolates could be assigned to A. alternata, 15 to the A. arborescens species complex and a single isolate to A. burnsii. The remaining 2% (3 isolates) represented sect. Infectoriae (single isolate) and sect. Pseudoulocladium (2 isolates). Population assignment analyses of the 137 A. alternata isolates suggested that subpopulations did not exist within the sample. The A. alternata isolates were thus divided into four artificial subpopulations to represent four quadrants of the USA. Forty-four isolates representing the south-western quadrant displayed the highest level of uniqueness based on private alleles, while the highest level of gene flow was detected between the south-eastern (32 isolates) and south-western quadrants. Genotypic diversity was high for all quadrants, and a test for linkage disequilibrium suggested that A. alternata has a cryptic sexual cycle. These statistics could be correlated with environmental factors, suggesting that indoor A. alternata isolates, although extremely diverse, have a continental distribution and high levels of gene flow over the continent.Dutch Ministry of Education, Culture and Science through an endowment of the FES programme ‘‘Making the tree of life work’’.http://www.elsevier.com/locate/yfgbihb201