Additions to the Mycosphaerella complex

Species in the present study were compared based on their morphology, growth characteristics in culture, and DNA sequences of the nuclear ribosomal RNA gene operon (including ITS1, ITS2, 5.8S nrDNA and the first 900 bp of the 28S nrDNA) for all species and partial actin and translation elongation factor 1-alpha gene sequences for Cladosporium species. New species of Mycosphaerella (Mycosphaerellaceae) introduced in this study include M. cerastiicola (on Cerastium semidecandrum, The Netherlands), and M. etlingerae (on Etlingera elatior, Hawaii). Mycosphaerella holualoana is newly reported on Hedychium coronarium (Hawaii). Epitypes are also designated for Hendersonia persooniae, the basionym of Camarosporula persooniae, and for Sphaerella agapanthi, the basionym of Teratosphaeria agapanthi comb. nov. (Teratosphaeriaceae) on Agapathus umbellatus from South Africa. The latter pathogen is also newly recorded from A. umbellatus in Europe (Portugal). Furthermore, two sexual species of Cladosporium (Davidiellaceae) are described, namely C. grevilleae (on Grevillea sp., Australia), and C. silenes (on Silene maritima, UK). Finally, the phylogenetic position of two genera are newly confirmed, namely Camarosporula (based on C. persooniae, teleomorph Anthracostroma persooniae), which is a leaf pathogen of Persoonia spp. in Australia, belongs to the Teratosphaeriaceae, and Sphaerulina (based on S. myriadea), which occurs on leaves of Fagaceae (Carpinus, Castanopsis, Fagus, Quercus), and belongs to the Mycosphaerellaceae

Cercosporoid leaf pathogens from whorled milkweed and spineless safflower in California

Two cercosporoid species are respectively described from Mexican whorled milkweed (Asclepias fascicularis), and spineless safflower (Carthamus tinctorius) from California. Passalora californica represents a new pathogen on Asclepias fascicularis, while Ramularia cynarae is confirmed on Carthamus tinctorius and Cynara cardunculus (Asteraceae), and an epitype designated. Pathogenicity is also established for both pathogens based on Koch’s postulate

What is Scirrhia?

The ascomycetous genus Scirrhia is presently treated as a member of Dothideomycetidae, though uncertainty remains as to which family it belongs in Capnodiales, Ascomycota. Recent collections on stems of a fern, Pteridium aquilinum (Dennstaedtiaceae) in Brazil, led to the discovery of a new species of Scirrhia, described here as S. brasiliensis. Based on DNA sequence data of the nuclear ribosomal DNA (LSU), Scirrhia is revealed to represent a member of Dothideomycetes, Capnodiales, Mycosphaerellaceae. Scirrhia is the first confirmed genus in Mycosphaerellaceae to have well developed pseudoparaphyses and a prominent hypostroma in which ascomata are arranged in parallel rows. Given the extremely slow growth rate and difficulty in obtaining cultures of S. brasiliensis on various growth media, it appears that Scirrhia represents a genus of potentially obligate plant pathogens within Mycosphaerellaceae

Pseudovirgaria, a fungicolous hyphomycete genus

The genus Pseudovirgaria, based on P. hyperparasitica, was recently introduced for a mycoparasite of rust sori of various species of Frommeëlla, Pucciniastrum and Phragmidium in Korea. In the present study, an older name introduced by Saccardo based on European material, Rhinotrichum griseum, is shown to resemble P. hyperparasitica. Morphological study and ITS barcodes from fresh collections of R. griseum from Austria on uredinia and telia of Phragmidium bulbosum on Rubus spp. reveal that it is distinct from P. hyperparasitica. The status of the genus Rhinotrichum, introduced for a fungus occurring on dry wood, remains unclear. Pseudovirgaria grisea comb. nov. is therefore proposed for the mycoparasite occurring on rust fungi in Europe, and an epitype is designated from the recent collections

High species diversity in Colletotrichum associated with citrus diseases in Europe

Species of Colletotrichum are considered important plant pathogens, saprobes, and endophytes on a wide range of plant hosts. Several species are well-known on citrus, either as agents of pre- or post-harvest infections, such as anthracnose, postbloom fruit drop, tear stain and stem-end rot on fruit, or as wither-tip of twigs. In this study we explored the occurrence, diversity and pathogenicity of Colletotrichum spp. associated with Citrus and allied genera in European orchards, nurseries and gardens. Surveys were carried out during 2015 and 2016 in Greece, Italy, Malta, Portugal and Spain. A total of 174 Colletotrichum strains were isolated from symptomatic leaves, fruits, petals and twigs. A multi-locus phylogeny was established based on seven genomic loci (ITS, GAPDH, ACT, CAL, CHS-1, HIS3 and TUB2), and the morphological characters of the isolates determined. Preliminary pathogenicity tests were performed on orange fruits with representative isolates. Colletotrichum strains were identified as members of three major species complexes. Colletotrichum gloeosporioides s.str. and two novel species (C. helleniense and C. hystricis) were identified in the C. gloeosporioides species complex. Colletotrichum karstii, C. novae-zelandiae and two novel species (C. catinaense and C. limonicola) in the C. boninense species complex, and C. acutatum s.str. was also isolated as member of C. acutatum species complex. Colletotrichum gloeosporioides and C. karstii were the predominant species of Colletotrichum isolated. This study represents the first report of C. acutatum on citrus in Europe, and the first detection of C. novae-zelandiae from outside New Zealand. Pathogenicity tests revealed C. gloeosporioides s.str. to be the most virulent species on fruits. The present study improves our understanding of species associated with several disease symptoms on citrus fruits and plants, and provides useful information for effective disease management

Molecular phylogenetic studies on the lichenicolous Xanthoriicola physciae reveal Antarctic rock-inhabiting fungi and Piedraia species among closest relatives in the Teratosphaeriaceae

The phylogenetic placement of the monotypic dematiaceous hyphomycete genus Xanthoriicola was investigated. Sequences of the nLSU region were obtained from 11 specimens of X. physciae, which formed a single clade supported both by parsimony (91 %), and maximum likelihood (100 %) bootstraps, and Bayesian Posterior Probabilities (1.0). The closest relatives in the parsimony analysis were species of Piedraria, while in the Bayesian analysis they were those of Friedmanniomyces. These three genera, along with species of Elasticomyces, Recurvomyces, Teratosphaeria, and sequences from unnamed rock-inhabiting fungi (RIF), were all members of the same major clade within Capnodiales with strong support in both analyses, and for which the family name Teratosphaeriaceae can be used pending further studies on additional taxa

Characterization of Mycosphaerellaceae species associated with citrus greasy spot in Panama and Spain

[EN] Greasy spot of citrus, caused by Zasmidium citri-griseum (= Mycosphaerella citri), is widely distributed in the Caribbean Basin, inducing leaf spots, premature defoliation, and yield loss. Greasy spot-like symptoms were frequently observed in humid citrus-growing regions in Panama as well as in semi-arid areas in Spain, but disease aetiology was unknown. Citrus-growing areas in Panama and Spain were surveyed and isolates of Mycosphaerellaceae were obtained from citrus greasy spot lesions. A selection of isolates from Panama (n = 22) and Spain (n = 16) was assembled based on their geographical origin, citrus species, and affected tissue. The isolates were characterized based on multi-locus DNA (ITS and EF-1 alpha) sequence analyses, morphology, growth at different temperatures, and independent pathogenicity tests on the citrus species most affected in each country. Reference isolates and sequences were also included in the analysis. Isolates from Panama were identified as Z. citri-griseum complex, and others from Spain attributed to Amycosphaerella africana. Isolates of the Z. citri-griseum complex had a significantly higher optimal growth temperature (26.8 degrees C) than those of A. africana (19.3 degrees C), which corresponded well with their actual biogeographical range. The isolates of the Z. citri-griseum complex from Panama induced typical greasy spot symptoms in 'Valencia' sweet orange plants and the inoculated fungi were reisolated. No symptoms were observed in plants of the 'Ortanique' tangor inoculated with A. africana. These results demonstrate the presence of citrus greasy spot, caused by Z. citri-griseum complex, in Panama whereas A. africana was associated with greasy spot-like symptoms in Spain.Research was partially funded by 'Programa de Formacion de los INIA Iberoamerica' and INIA RTA2010-00105-00-00-FEDER to Vidal Aguilera Cogley.. We thank J. Martinez-Minaya (UV) for assistance with INLAAguilera-Cogley, VA.; Berbegal Martinez, M.; Català, S.; Collison Brentu, F.; Armengol Fortí, J.; Vicent Civera, A. (2017). Characterization of Mycosphaerellaceae species associated with citrus greasy spot in Panama and Spain. PLoS ONE. 12(12):1-19. https://doi.org/10.1371/journal.pone.0189585S1191212Crous, P. W., Summerell, B. A., Carnegie, A. J., Wingfield, M. J., Hunter, G. C., Burgess, T. I., … Groenewald, J. Z. (2009). Unravelling Mycosphaerella: do you believe in genera? Persoonia - Molecular Phylogeny and Evolution of Fungi, 23(1), 99-118. doi:10.3767/003158509x479487Mondal, S. N., & Timmer, L. W. (2006). Greasy Spot, a Serious Endemic Problem for Citrus Production in the Caribbean Basin. Plant Disease, 90(5), 532-538. doi:10.1094/pd-90-0532Whiteside, J. O. (1970). Etiology and Epidemiology of Citrus Greasy Spot. Phytopathology, 60(10), 1409. doi:10.1094/phyto-60-1409Huang, F., Groenewald, J. Z., Zhu, L., Crous, P. W., & Li, H. 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Pseudocercospora piperis associated with leaf spots on Piper aduncum in Brazil

Piper aduncum (Piperaceae) is a neotropical plant that has been widely exploited as a medicinal plant in its native range but has recently become an important invasive plant species in Papua New Guinea. A cercosporoid fungus was recently found associated with leaf spots on this plant in the Amazon. The morphology of the fungus is typical of Pseudocercospora piperis, a fungus that has never been recorded on this host species in Brazil. © 2013 Australasian Plant Pathology Society Inc