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ABSTRACTThis is the sixth contribution in a series devoted to the phylogeny and taxonomy of powdery mildews. This part includes our third treatment of the species of the genus Erysiphe. It continues the previous contribution on the phylogenetic-taxonomic assessment of the species belonging to the “Microsphaeralineage.” Since this is a large lineage, we have split the treatment of the “Microsphaeralineage” into two parts. Phylogenetic trees based on rDNA are supplemented by sequences of additional markers (CAM, GAPDH, GS, RPB2, and TUB). The “Erysiphe trifoliorumcomplex” is a challenging group that belongs to the “Microsphaeralineage.” Adequate clarification of this complex will be possible when additional worldwide multilocus sequence analyses are performed. The new species Erysiphe acetosae, E. acmisponis, E. lathyrina, E. salmoniana, and E. santalicolaare described, and the new combinations E. biuncinataand E. pavoniaeare introduced. Specimens of several species have been sequenced for the first time, particularly North American species, such as Erysiphe caryae, E. ceanothi, E. juglandis-nigrae, and E. ravenelii. Erysiphe syringaeis lectotypified and 15 species names are epitypified in order to provide ex-epitype reference sequences. For other species, non-ex-type reference sequences are proposed for phylogenetic-taxonomic purposes. Ex-type sequences for Erysiphe baptisiicola, E. sesbaniae, Microsphaera sydowiana, M. umbilici, and Oidium pavoniaehave been retrieved.

ABSTRACTIn this contribution, we offer the fifth installment of a series focusing on the phylogeny and taxonomy of powdery mildews. This paper is the second segment evaluating the genus Erysiphe. The first treatment of Erysiphefocused on phylogenetically basal species in the “Uncinulalineage.” This research presents a phylogenetic-taxonomic assessment of species that form the group previously referred to as the “Microsphaeralineage.” Given the size of the group, we split the treatment of this lineage of Erysiphespecies into two parts based on their phylogenetic placement. Phylogenetic trees based on ITS+28S data are supplemented by sequences of additional markers (CAM, GADPH, GS, RPB2, and TUB). Included in the analysis of the Microsphaeralineage is the “Erysiphe aquilegiaecomplex” (group, clade, cluster), which encompasses sequences obtained from an assemblage of Erysiphespecies with insufficient resolution in rDNA analyses. Attempts have been made to resolve this group at the species level by applying a multilocus approach. A detailed discussion of the “Erysiphe aquilegiaecomplex” is provided. Sequences are provided for the first time for several species, particularly North American species, such as Erysiphe aggregata, E. erineophila, E. parnassiae, and E. semitosta. Ex-type sequences for Microsphaera benzoinand M. magnusiihave been retrieved. Alphitomorpha penicillata, Microsphaera vanbruntiana, and M. symphoricarpiare epitypified with ex-epitype sequences. The new species Erysiphe alnicola, E. deutziana, E. cornigena, E. lentaginis, and E. sambucinaare described, the new combinations E. lauracearum, E. passiflorae, and E. sambucicolaare introduced, and the new name E. santaliis proposed.

ABSTRACTThis is the fourth contribution within an ongoing series dedicated to the phylogeny and taxonomy of powdery mildews. This particular installment undertakes a comprehensive evaluation of a group previously referred to as the “Uncinula lineage” within Erysiphe. The genus Erysipheis too large to be assessed in a single paper; thus, the treatment of Erysipheis split into three parts, according to phylogenetic lineages. The first paper, presented here, discusses the most basal lineage of Erysipheand its relationship to allied basal genera within tribe Erysipheae (i.e., Brasiliomycesand Salmonomyces). ITS+28S analyses are insufficient to resolve the basal assemblage of taxa within the Erysipheae. Therefore, phylogenetic multilocus examinations have been carried out to better understand the evolution of these taxa. The results of our analyses favor maintaining Brasiliomyces, Bulbomicroidium, and Salmonomycesas separate genera, at least for the interim, until further phylogenetic multilocus data are available for additional basal taxa within the Erysipheae. The current analyses also confirmed previous results that showed that the “Uncinula lineage” is not exclusively composed of Erysiphespecies of sect. Uncinulabut also includes some species that morphologically align with sect. Erysiphe, as well as species that had previously been assigned to Californiomycesand Typhulochaeta. Numerous sequences of Erysiphespecies from the “Uncinula lineage” have been included in the present phylogenetic analyses and were confirmed by their position in well-supported species clades. Several species have been sequenced for the first time, including Erysiphe clintonii, E. couchii, E. geniculata, E. macrospora, and E. parvula. Ex-type sequences are provided for 16 taxa including E. nothofagi, E. trinae, and E. variabilis. Epitypes are designated and ex-epitype sequences are added for 18 taxa including Erysiphe carpophila, E. densa, and U. geniculatavar. carpinicola. The new species Erysiphe canariensisis described, and the new names E. hosagoudariiand E. pseudoprunastriand the new combination E. ampelopsidisare introduced.

ABSTRACTThe genus Rhododendroncomprises over 1000 evergreen and deciduous species. In the Pacific Northwest Coast region of North America (PNWC), powdery mildews infecting deciduous Rhododendronspp. are well documented but less so on evergreen Rhododendronspp. Infections of both groups of hosts historically have been attributed to Erysiphe azaleaeor E. vaccinii. No formal characterizations of powdery mildew fungi infecting either deciduous or evergreen Rhododendronspp. in the PNWC have been completed. The objectives of this study were to identify the powdery mildew pathogens infecting evergreen Rhododendronspp. in the PNWC and to assess the phylogenetic position of these fungi within the Erysiphaceae. To ascertain valid taxonomic conclusions, and to determine whether potential introductions of exotic Rhododendronpowdery mildews in North America have occurred, it was necessary to put the new North American phylogenetic data into a worldwide context. Therefore, available phylogenetic data from all Erysiphespp. on Rhododendronhave been included in our analyses.Based on analyses of numerous new internal transcribed spacer (ITS) and 28S rDNA sequences and already available sequences deposited in GenBank retrieved from evergreen and deciduous Rhododendronspp., the following Erysiphespp. could be phylogenetically confirmed (all belonging to Erysiphesect. Microsphaera): Erysiphe azaleaenom. cons. (Oidium ericinumcould be verified as a synonym), E. digitata(holotype sequenced), E. izuensis, and E. vaccinii. Erysiphe azaleaeand E. vacciniiare epitypified with sequenced specimens, and an ex-neotype sequence has been obtained for Oidium ericinum. Erysiphe rhododendri(Erysiphesect. Erysiphe), only known from two collections in India (Himalayan region), was not available for phylogentic analyses.

ABSTRACTThe genus Lupinus(Fabaceae) consists of over 250 plant species located throughout the world. Powdery mildew, caused by Erysiphespecies, is a common disease infecting these ecologically, ornamentally, and agriculturally important plants. In the present work, we conducted phylogenetic and taxonomic analyses on Erysiphespecies colonizing hosts of the leguminous genus Lupinus, using sequences from the internal transcribed spacer (ITS) and 28S genomic regions. Powdery mildews of the genus Erysipheon Fabaceae are taxonomically intricate and challenging. Therefore, it is necessary to phylogenetically analyze the DNA retrieved from powdery mildew on lupines in a broad context that includes common and allied powdery mildew species that occur on a range of leguminous plants such as Erysiphe astragali, E. baeumleri, E. pisi, and E. trifoliorum. A new species Erysiphe lupini, found in the USA on Lupinus lepidus, L. polyphyllus, and Lupinussp., is described. Additionally, Erysiphe intermedia(≡ Microsphaera trifoliivar. intermedia) has been confirmed as a North American lupine powdery mildew that is a sister species to E. astragalion Astragalusspp. European Erysiphecollections on lupines were often referred to as E. intermedia, but our analyses have shown that they pertain to E. trifoliorum. The E. trifoliorumclade is composed of several species (i.e. E. baeumleri, E. euonymi, E. hyperici,and E. trifoliorum), that cannot be sufficiently resolved based solely on ITS+28S sequences. Morphological and biological differences between the species are discussed and provide evidence that the species concerned should be maintained. Finally, a sequence obtained from a powdery mildew collected in Portugal on the native Lupinus micranthuspertained to the Erysiphe guarinoniiclade. This collection is tentatively treated as Erysiphesp. To fix the application of the species names E. astragali, E. baeumleri(including its synonym E. marchica), and E. intermedia, epitypes have been designated with ex-epitype sequences.

ABSTRACTErysiphespecies (powdery mildews) on Corylusand Ostryahosts (Betulaceae subfam. Coryloideae) in Asia and North America are widespread pathogens on these economically and ecologically valuable nut crops. An improved understanding of their phylogeny and taxonomy is of ecological and applied importance. Phylogenetic analyses and morphological reexaminations conducted in this study revealed a higher degree of diversity and cryptic speciation than reflected in earlier species concepts. North American collections on C. cornuta, which were previously assigned to E. corylacearum, proved to constitute a species of its own and are herein introduced as E. cornutae, sp. nov. Two additional North American species, E. coryli-americanae, sp. nov. and E. ostryae, sp. nov., have been detected on C. americanaand O. virginianaand are described. They are morphologically similar to E. cornutae, but genetically distinct. Based on phylogenetic analyses, E. corylacearumis an Asian species confined to various Asian Corylusspecies. Sequence data retrieved from Japanese type material of E. corylicolarevealed that this species clusters with sequences from E. elevataon Catalpaspecies, distant from all other Erysiphespecies on Corylus. Morphologically similar, yet distinct, specimens on C. sieboldiana, which were previously assigned to E. corylicola, form a distinct, distant clade. The species involved is described herein as E. pseudocorylacearum, sp. nov. Additionally, an unusual infection of C. sieboldianain Japan by E. syringaehas been shown by means of sequence data. The phylogeny and taxonomy of Erysiphespecies belonging to the Corylioideae are discussed in detail, and a key to the species concerned is provided.

ABSTRACTPodosphaera tridactyla(s. lat.) is a powdery mildew species occurring on a wide range of Prunusspp. almost worldwide. We have investigated the phylogeny of the Po. tridactylacomplex, with special emphasis on potential aspects of cryptic speciation. The results suggested that Po. tridactylarepresents a species complex consisting of at least 12 different species. Based on detailed morphological examinations and molecular sequence analyses, we propose dividing Po. tridactylas. lat. into 10 species, encompassing 7 new species (Po. ampla, Po. pruni-avium, Po. pruni-cerasoidis, Po. prunigena, Po. pruni-lusitanicae, Po. prunina, and Po. pruni-japonicae) and 3 known species (Po. longiseta, Po. salatai, and Po. tridactylas. str.). Oidium passeriniion Pr. laurocerasusis confirmed as a synonym of Po. tridactylas. str. Epitypes are designated for Po. tridactylaand Oidium passerinii.

ABSTRACTPowdery mildew of Prunusspp. is a significant disease in most cherry growing regions of Washington, USA. Powdery mildews on Prunus virginianaand Pr. aviumwere previously assigned to Podosphaera clandestinas. lat. (= Po. oxyacanthae) or Po. prunicola. In this report, we confirm the presence of two distinct Podosphaeraspecies on these hosts. Phylogenetic analyses of nuc rDNA sequences from the internal transcribed spacer region (ITS1-5.8S-ITS2 = ITS) and 28S subunit confirmed the presence of two distinct species. A morphological comparison with type material of Po. prunicolaand additional collections demonstrated that the powdery mildew on Pr. virginiana(including var. demissaand var. melanocarpa) is in fact Po. prunicola. The powdery mildew on Pr. aviumis genetically, morphologically, and biologically distinct from Po. prunicolaand is described here as the new species Po. cerasi. Cross-inoculation experiments confirmed that these two species are host specific. Podosphaera prunicolawas unable to colonize Pr. avium, whereas Po. cerasiwas unable to colonize Pr. virginiana. Morphological reexamination of numerous specimens identified as Po. prunicolaon a broad range of Prunusspecies suggests that Po. prunicolais probably confined to species in Prunussubgen.Padus(= Prunussubgen. Cerasussect. Laurocerasus, including sect. Padus), with Pr. virginianaas the principal host. Podosphaera cerasioccurs on hosts in Prunussubgen. Cerasus, and our work confirms a newly described species of powdery mildew on Pr. avium. This work also includes the first documented and genetically proven European record of Po. prunicolaon Pr. serotinaand its widespread occurrence in the United States.

ABSTRACTThe taxonomic history of the common powdery mildew of Chrysanthemum× morifolium(chrysanthemum, florist’s daisy), originally described in Germany as Oidium chrysanthemi, is discussed. The position of O. chrysanthemiwas investigated on the basis of morphological traits and molecular phylogenetic analyses. Based on the results of this study, this species, which is closely related to Golovinomyces artemisae, was reassessed and reallocated to Golovinomyces. The phylogenetic analysis and taxonomic reassessment of the chrysanthemum powdery mildew is supplemented by a morphological description, a summary of its worldwide distribution data, and a brief discussion of the introduction of this fungus to North America. G. chrysanthemidiffers from true G. artemisiaein that it has much longer conidiophores, is not constricted at the base, and has much larger and most importantly longer conidia. The close affinity of Golovinomycesto Artemisiaand Chrysanthemumspecies signifies a coevolutionary event between the powdery mildews concerned and their host species in the subtribe Artemisiinae(Asteraceaetribe Anthemideae). This conclusion is fully supported by the current phylogeny and taxonomy of the host plant genera and the coevolution that occurred with the host and pathogen. The following powdery mildew species, which are associated with hosts belonging to the tribe Anthemideaeof the Asteraceae, are epitypified: Alphitomorpha depressaβ artemisiae(≡ Alphitomorpha artemisiae), Erysiphe artemisiae, and Oidium chrysanthemi. Erysiphe macrocarpais neotypified. Their sequences were retrieved from the epitype collections and have been added to the phylogenetic tree. Golovinomyces orontii, an additional powdery mildew species on Chrysanthemum×morifolium, is reported. This species is rarely found as a spontaneous infection and was obtained from inoculation experiments.

Of the 17 genera of the Erysiphaceae, only four genera (viz. Leveillula, Phyllactinia, Pleochaetaand Queirozia) exhibit (partly) endoparasitism. To investigate early evolution of this endoparasitic nature, we performed molecular phylogenetic analyses of powdery mildews belonging to the tribe Phyllactinieae collected in North and South America. The most ancestral taxa in the tribe Phyllactinieae belong to the Pleochaeta/Queiroziagroup, from which the genus Phyllactiniawas derived. Finally, the truly endoparasitic genus Leveillulaemerged from a part of Phyllactinia. The present study showed clear evolutional polarity in the powdery mildews concerned (that is, partly endoparasitic group evolved from ectoparasitic group) and then a truly endoparasitic group emerged from a partly endoparasitic group. In addition, a group with distinctly dimorphic conidia proved to be basal in the Phyllactinieae, and a group without distinctly dimorphic conidia was derived from that group. The present analyses clearly showed that Leveilluladerived from a part of the “Basal Phyllactiniagroup”. However, all sister taxa to Leveillulawere distributed in North and South America. Because the putative geographic origin of Leveillulais assumed to be Central and Western Asia or the Mediterranean region, we postulate a missing link during the evolution of Leveillulafrom Phyllactinia. Based on the present phylogenetic studies and the new rules of the International Code of Nomenclature for algae, fungi, and plants (McNeill et al. 2012), the following new species and taxonomic re-allocations are proposed: Phyllactinia bougainvilleaesp. nov., Ph. caricaecomb. nov., Ph. caricicolacomb. nov., Ph. durantaecomb. nov., Ph. leveilluloidessp. nov., Ph. obclavatacomb. nov., and Ph. papayaecomb. nov.

Powdery mildew on cherry bark oak (Quercus falcatevar. pagodifolia) collected in Tennessee, USA, was determined to be Erysiphe abbreviata, a species confined to North America. The diagnostically important anamorph of this species is described for the first time. Sequence analyses of the rDNA ITS region and D1/D2 domains of the 28S rDNA were used to obtain phylogenetic data for and taxonomic conclusions about this species. The structure of the anamorph (Oidiumsubgen. Pseudoidium) and the molecular data support the placement of this species in Erysipheemend. (including Microsphaera) as a species separate from the Eurasian Erysiphe alphitoides.

The genus Cercosporais one of the largest and most heterogeneous genera of hyphomycetes. Cercosporaspecies are distributed worldwide and cause Cercospora leaf spot on most of the major plant families. Numerous species described from diverse hosts and locations are morphologically indistinguishable from C. apiiand subsequently are referred to as C. apii sensu lato. The importance and ecological role that different hosts play in taxon delimitation and recognition within this complex remains unclear. It has been shown that Cercospora leaf spot on celery and sugar beet are caused respectively by C. apiiand C. beticola, both of which are part of the C. apiicomplex. During this study we characterized a new Cercosporaspecies, C. apiicola, which was isolated from celery in Venezuela, Korea and Greece. The phylogenetic relationship between C. apiicolaand other closely related Cercosporaspecies was studied with five different gene areas. These analyses revealed that the C. apiicolaisolates cluster together in a well defined clade. Both C. apiiand C. beticola sensu strictoform well defined clades and are shown to have wider host ranges and to represent distinct species.

AbstractAnamorph genera associated with Mycosphaerellaare separated on a combination of characters such as conidiomatal structure, the nature and arrangement of conidiophores, conidiogenesis, dehiscence scars and pigmentation. To date 27 genera have been reported as anamorphs of Mycosphaerella, 19 of which were included in this study. Based on the phylogeny of the ITS1, 5.8S, and ITS2 rDNA sequence data, Mycosphaerellaproved to be monophyletic. The major group consisted of several small clusters correlating to specific anamorph genera, as well as other clusters containing an assemblage of anamorph genera. Although Mycosphaerellais monophyletic, it appears that many of the morphological characters defining different anamorph genera evolved more than once and for the most part do not represent true groups within Mycosphaerella.Nevertheless, the anamorph generic concepts contain valuable information of practical use to plant pathologists and mycologists working with these organisms. Based on these results, as well as a re-evaluation of the criteria upon which anamorph genera are distinguished in this complex, a reduced set of informative criteria and genera are proposed. The degree of scar thickening, darkening and refraction, as well as the presence or absence of pigmentation in conidiophores and conidia still appear to be useful features delimiting anamorph genera of Mycosphaerella.