Comprehensive phylogenetic analysis of the genus Golovinomyces (Ascomycota: Erysiphales) reveals close evolutionary relationships with its host plants

First Report of Powdery Mildew Caused by Golovinomyces ambrosiae on Solanum carolinense in Korea

Solanum carolinense L. (Solanaceae) is a perennial herbaceous plant native to the southeastern United States. The plant has been invasive in Europe, Australia, and Asia. It was accidentally introduced to Korea in the 1960s (Oh et al. 2002) and is now widely naturalized mostly in the southern area of the Korean peninsula. Since 2002, it has been designated as one of 'harmful non-indigenous plants' by the Korean Ministry of Environment due to its adverse effects on native plants. In September 2014, several S. carolinense plants were found infested with a powdery mildew disease in Busan, which was the first for Korea. Later in 2020-2022, hundreds of plants were continuously observed with an approximately 50% disease incidence in Jeonju, Korea. Symptoms first appeared as circular to irregular white patches, which subsequently coalesced to develop into abundant hyphal growth on both sides of the leaves. Representative voucher specimens were deposited in the Korea University herbarium (KUS-F28240 and F32541). Hyphal appressoria were nipple-shaped. Conidiophores were cylindrical, 110 to 190 × 10 to 12 µm, and produced 2 to 5 immature conidia in chains with a sinuate outline. Foot-cells of conidiophores were straight, cylindrical, and 58 to 90 μm long, followed by 2 to 3 cells. Conidia were ellipsoid to barrel-shaped, 29 to 36 × 15 to 20 μm (l/w 1.6 to 2.0), and devoid of distinct fibrosin bodies. Germ tubes were at the perihilar position of the conidia. Sexual stage was not developed. These morphological characteristics are consistent with those of Golovinomyces ambrosiae (Schwein.) U. Braun & R.T.A. (Braun and Cook 2012). Sequences of the internal transcribed spacer (ITS) region and large subunit (LSU) gene of rDNA were determined using primer pairs ITS1/PM6 and PM3/TW14, respectively (Bradshaw and Tobin 2020). A comparison of the resulting sequences using the BLASTn algorithm showed 100% identity with reference sequences of G. ambrosiae (MT355556, AB769425) and G. spadiceus (MN365027) for ITS and LSU in NCBI. Obtained sequences were deposited in GenBank (Accession Nos: OP585651-OP585654). A Maximum parsimony tree was constructed based on ITS+LSU dataset consisting of 23 sequences. Our sequences were clustered with sequences of G. ambrosiae, G. latisporus and G. cichoracearum, and supported with 100% BS value. A pathogenicity test was performed by gently dusting conidia onto leaves of five healthy potted plants. Five non-inoculated plants served as controls. Powdery mildew colonies developed on all inoculated plants after 5 days, whereas the control plants remained symptomless. The fungus present on the inoculated leaves was morphologically identical to that observed on the originally diseased leaves, which supports Koch's postulate. Previously, Erysiphe cichoracearum (syn. of G. cichoracearum) was recorded on this plant in theUSA (Farr and Rossman 2022). Since G. cichoracearum has been divided into several distinct species (Takamatsu et al. 2013, Qiu et al. 2020), the current taxonomic position of the North American isolate is unknown. In Korea, G. ambrosiae was reported on several asteraceous hosts such as Bellis perennis, Brachyscome multifida, Helianthus annuus, H. salicifolius, and Verbena bonariensis (Farr and Rossman 2022). To our knowledge, this is the first report of powdery mildew on this plant outside the USA. According to our field observations, powdery mildew infestation had little effect on plant growth and vigor.   References: Braun, U., and Cook, R. T. A. 2012. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No. 11. CBS, Utrecht, Netherlands. Bradshaw, M., and Tobin, P.C. 2020. Phytopathology 110:1248. Farr, D. F., and Rossman, A. Y. Fungal Databases, Syst. Mycol. Microbiol. Lab., Online publication. ARS, USDA. Retrieved October 5, 2022. Oh, S. M., et al. 2002. Kor. J. Weed Sci. 22:280. Qiu, P-L., et al. 2020. BMC Microbiology 20:51. Takamatsu S., et al. 2013. Mycologia 105:1135.

Phylogeny and taxonomy of the genera of Erysiphaceae, part 1: Golovinomyces

Powdery mildews are a monophyletic group of obligate plant pathogenic fungi in the family Erysiphaceae. Powdery mildews are economically important in that they cause damage to many agriculturally significant crops and plants in ecologically important habitats. In this contribution, we introduce a new series of publications focusing on the phylogeny and taxonomy of this group, with an emphasis on specimens collected from North America. The first part of the series focuses on the genus Golovinomyces and includes a section detailing the powdery mildew species concept. We conducted analyses of Golovinomyces spp. with available rDNA sequence data from GenBank and supplemented the data set with rDNA (ITS, 28S, IGS) as well as protein-coding (GAPDH) data from 94 North American collections. Many of the species evaluated are included in phylogenetic and morphological analyses for the first time, including the American species G. americanus, G. brunneopunctatus, G. californicus, G. greeneanus, G. hydrophyllacearum, and G. sparsus. A special emphasis was placed on acquiring ex-type or ex-epitype sequences or presenting reference sequences for phylogenetic-taxonomic purposes. Three new species, G. eurybiarum, G. galiorum, and G. malvacearum, are described, and the new combinations G. fuegianus, G. mutisiae, and G. reginae are introduced. Ex-holotype sequences of Erysiphe sparsa (≡ G. sparsus) reveal that it should be reduced to synonymy with G. ambrosiae, and ex-epitype sequences of G. valerianae reveal that it should be reduced to synonymy with G. orontii. Multiple epitypes are designated with ex-epitype sequences.

Current Insight into Traditional and Modern Methods in Fungal Diversity Estimates

Fungi are an important and diverse component in various ecosystems. The methods to identify different fungi are an important step in any mycological study. Classical methods of fungal identification, which rely mainly on morphological characteristics and modern use of DNA based molecular techniques, have proven to be very helpful to explore their taxonomic identity. In the present compilation, we provide detailed information on estimates of fungi provided by different mycologistsover time. Along with this, a comprehensive analysis of the importance of classical and molecular methods is also presented. In orderto understand the utility of genus and species specific markers in fungal identification, a polyphasic approach to investigate various fungi is also presented in this paper. An account of the study of various fungi based on culture-based and cultureindependent methods is also provided here to understand the development and significance of both approaches. The available information on classical and modern methods compiled in this study revealed that the DNA based molecular studies are still scant, and more studies are required to achieve the accurate estimation of fungi present on earth.

A Snapshot Picture of the Fungal Composition of Bee Bread in Four Locations in Bulgaria, Differing in Anthropogenic Influence

Information about the fungal composition of bee bread, and the fermentation processes to which the fungi contribute significantly, is rather scarce or fragmentary. In this study, we performed an NGS-based metagenomics snapshot picture study of the fungal composition of bee bread in four locations in Bulgaria during the most active honeybee foraging period at the end of June 2020. The sampling locations were chosen to differ significantly in climatic conditions, landscape, and anthropogenic pressure, and the Illumina 2 × 250 paired-end reads platform was used for amplicon metagenomics study of the ITS2 region. We found that some of the already reported canonical beneficial core fungal species were present within the studied samples. However, some fungal genera such as Monilinia, Sclerotinia, Golovinomyces, Toxicocladosporium, Pseudopithomyces, Podosphaera and Septoriella were reported for the first time among the dominant genera for a honeybee related product. Anthropogenic pressure negatively influences the fungal composition of the bee bread in two different ways-urban/industrial pressure affects the presence of pathogenic species, while agricultural pressure is reflected in a decrease of the ratio of the beneficial fungi.

First Report of Powdery Mildew Caused by Golovinomyces ambrosiae on Bidens pilosa in China

Bidens pilosa L., (spanish needle), is a wild, flowering plant of Asteraceae, that is grown in gardens, fields, roadsides, and riverbanks in Fuzhou, China. It is also used in traditional folk medicine for a broad range of ailments in China. In March 2019 and 2020, hundreds of B. pilosa growing along the roadsides, and gardens in the districts of Minhou and Jinshan were observed to be severely affected by a powdery mildew with approximately 80% disease incidence. Symptoms appeared as circular to irregular small white, powdery patches, typically on the adaxial sides of leaves and progressed to coalescent colonies on the leaves. As the disease developed, the infected leaves became wilted and senesced. Mycelia on leaves were superficial and solitary appressoria were slightly to distinctly nipple-shaped. Conidiophores were erect, 120 to 230 × 10 to 12 µm, and produced two to five conidia in chains with a sinuate outline. Foot-cells were erect, cylindrical, and 60 to 110 μm long. Conidia were hyaline, ellipsoid to barrel-shaped, 26 to 40 × 18 to 24 μm, and devoid of distinct fibrosin bodies. Germ tubes were long and produced at the perihilar position of the conidia. No chasmothecia were observed. Morphological characteristics overlapped with Golovinomyces ambrosiae, G. cichoracearum, and G. spadiceus (Braun and Cook 2012) on hosts within the Asteraceae tribe Heliantheae (Takamatsu et al. 2013). For molecular identification, ITS and IGS regions as well as partial LSU of two representative collections (MJU-IM019- MJU-IM020), were amplified using ITS1/ITS4, IGS-12a/ NS1R and LSU1/LSU2 primers (Carbone & Kohn, 1999; Scholin et al. 1994; White et al. 1990), respectively. The resulting sequences were deposited in GenBank (ITS: MW965777, MW965778; LSU: MW965787, MW965788; IGS: MW981256, MW981257). A BLAST search revealed 99 to 100 % sequence similarity to G. ambrosiae sequences (KX987303, AB769421, AB077689, AB769426, AB077643, and AB769425). Phylogenetic analysis of ITS, LSU and IGS also grouped obtained sequences within the G. ambrosiae complex (Qiu et al. 2020). Pathogenicity was confirmed through inoculation by gently pressing infected leaves onto leaves of five healthy, potted, young B. pilosa plants, while five non-inoculated plants served as controls. All plants were maintained in a greenhouse at 25 ± 2°C. Inoculated plants developed symptoms after 7 to 10 days, whereas the control plants remained symptomless. The morphology of the resulting fungus on inoculated plants was identical to that originally observed on diseased plants. Podosphaera spp., have been reported on B. pilosa (Farr & Rossman 2021) from North America, Africa, and Asia. To our knowledge, this is the first report of powdery mildew caused by G. ambrosiae on B. pilosa in China and Asia. Wild populations of B. pilosa may be the primary source of powdery mildew inoculum for commercial Asteraceae members and may warrant consideration in the control of this disease. References: Braun, U., and Cook, R. T. A. 2012. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No. 11. CBS, Utrecht, The Netherlands. Carbone, I., and Kohn, L. M. 1999. Mycologia 91:553. Farr, D. F., and Rossman, A. Y. 2021. Fungal Databases. Syst. Mycol. Microbiol. Lab., USDA ARS, 18 April 2021. Qiu, P. L., et al. 2020. BMC Microbiol. 20:1. Scholin, C. A., et al. 1994. J. Phycol. 30:999. Takamatsu, S., et al. 2013. Mycologia 105:1135. White, T. J., et al. 1990. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA.

One stop shop IV: taxonomic update with molecular phylogeny for important phytopathogenic genera: 76–100 (2020)

This is a continuation of a series focused on providing a stable platform for the taxonomy of phytopathogenic fungi and fungus-like organisms. This paper focuses on one family: Erysiphaceae and 24 phytopathogenic genera: Armillaria, Barriopsis, Cercospora, Cladosporium, Clinoconidium, Colletotrichum, Cylindrocladiella, Dothidotthia,, Fomitopsis, Ganoderma, Golovinomyces, Heterobasidium, Meliola, Mucor, Neoerysiphe, Nothophoma, Phellinus, Phytophthora, Pseudoseptoria, Pythium, Rhizopus, Stemphylium, Thyrostroma and Wojnowiciella. Each genus is provided with a taxonomic background, distribution, hosts, disease symptoms, and updated backbone trees. Species confirmed with pathogenicity studies are denoted when data are available. Six of the genera are updated from previous entries as many new species have been described.

Australia: A Continent Without Native Powdery Mildews? The First Comprehensive Catalog Indicates Recent Introductions and Multiple Host Range Expansion Events, and Leads to the Re-discovery of Salmonomyces as a New Lineage of the Erysiphales

In contrast to Eurasia and North America, powdery mildews (Ascomycota, Erysiphales) are understudied in Australia. There are over 900 species known globally, with fewer than currently 60 recorded from Australia. Some of the Australian records are doubtful as the identifications were presumptive, being based on host plant-pathogen lists from overseas. The goal of this study was to provide the first comprehensive catalog of all powdery mildew species present in Australia. The project resulted in (i) an up-to-date list of all the taxa that have been identified in Australia based on published DNA barcode sequences prior to this study; (ii) the precise identification of 117 specimens freshly collected from across the country; and (iii) the precise identification of 30 herbarium specimens collected between 1975 and 2013. This study confirmed 42 species representing 10 genera, including two genera and 13 species recorded for the first time in Australia. In Eurasia and North America, the number of powdery mildew species is much higher. Phylogenetic analyses of powdery mildews collected from Acalypha spp. resulted in the transfer of Erysiphe acalyphae to Salmonomyces, a resurrected genus. Salmonomyces acalyphae comb. nov. represents a newly discovered lineage of the Erysiphales. Another taxonomic change is the transfer of Oidium ixodiae to Golovinomyces. Powdery mildew infections have been confirmed on 13 native Australian plant species in the genera Acacia, Acalypha, Cephalotus, Convolvulus, Eucalyptus, Hardenbergia, Ixodia, Jagera, Senecio, and Trema. Most of the causal agents were polyphagous species that infect many other host plants both overseas and in Australia. All powdery mildews infecting native plants in Australia were phylogenetically closely related to species known overseas. The data indicate that Australia is a continent without native powdery mildews, and most, if not all, species have been introduced since the European colonization of the continent.

Multi-locus phylogeny and taxonomy of an unresolved, heterogeneous species complex within the genus Golovinomyces (Ascomycota, Erysiphales), including G. ambrosiae, G. circumfusus and G. spadiceus

Background

Previous phylogenetic analyses of species within the genus Golovinomyces (Ascomycota, Erysiphales), based on ITS and 28S rDNA sequence data, revealed a co-evolutionary relationship between powdery mildew species and hosts of certain tribes of the plant family Asteraceae. Golovinomyces growing on host plants belonging to the Heliantheae formed a single lineage, comprised of a morphologically differentiated complex of species, which included G. ambrosiae, G. circumfusus, and G. spadiceus. However, the lineage also encompassed sequences retrieved from Golovinomyces specimens on other Asteraceae tribes as well as other plant families, suggesting the involvement of a plurivorous species. A multilocus phylogenetic examination of this complex, using ITS, 28S, IGS (intergenic spacer), TUB2 (beta-tubulin), and CHS1 (chitin synthase I) sequence data was carried out to clarify the discrepancies between ITS and 28S rDNA sequence data and morphological differences. Furthermore, the circumscription of species and their host ranges were emended.

Results

The phylogenetic and morphological analyses conducted in this study revealed three distinct species named, viz., (1) G. ambrosiae emend. (including G. spadiceus), a plurivorous species that occurs on a multitude of hosts including, Ambrosia spp., multiple species of the Heliantheae and plant species of other tribes of Asteraceae including the Asian species of Eupatorium; (2) G. latisporus comb. nov. (≡ Oidium latisporum), the closely related, but morphologically distinct species confined to hosts of the Heliantheae genera Helianthus, Zinnia, and most likely Rudbeckia; and (3) G. circumfusus confined to Eupatorium cannabinum in Europe.

Conclusions

The present results provide strong evidence that the combination of multi-locus phylogeny and morphological analysis is an effective way to identify species in the genus Golovinomyces.

Floral and Foliar Source Affect the Bee Nest Microbial Community

Managed pollinators such as the alfalfa leafcutting bee, Megachile rotundata, are essential to the production of a wide variety of agricultural crops. These pollinators encounter a diverse array of microbes when foraging for food and nest-building materials on various plants. To test the hypothesis that food and nest-building source affects the composition of the bee-nest microbiome, we exposed M. rotundata adults to treatments that varied both floral and foliar source in a 2 × 2 factorial design. We used 16S rRNA gene and internal transcribed spacer (ITS) sequencing to capture the bacterial and fungal diversity of the bee nests. We found that nest microbial communities were significantly different between treatments, indicating that bee nests become inoculated with environmentally derived microbes. We did not find evidence of interactions between the fungi and bacteria within our samples. Furthermore, both the bacterial and fungal communities were quite diverse and contained numerous exact sequence variants (ESVs) of known plant and bee pathogens that differed based on treatment. Our research indicates that bees deposit plant-associated microbes into their nests, including multiple plant pathogens such as smut fungi and bacteria that cause blight and wilt. The presence of plant pathogens in larval pollen provisions highlights the potential for bee nests to act as disease reservoirs across seasons. We therefore suggest that future research should investigate the ability of bees to transmit pathogens from nest to host plant.

Phylogeny and taxonomy of Podosphaera cerasi, sp. nov., and Podosphaera prunicola sensu lato

Powdery mildew of Prunus spp. is a significant disease in most cherry growing regions of Washington, USA. Powdery mildews on Prunus virginiana and Pr. avium were previously assigned to Podosphaera clandestina s. lat. (= Po. oxyacanthae) or Po. prunicola. In this report, we confirm the presence of two distinct Podosphaera species 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. prunicola and additional collections demonstrated that the powdery mildew on Pr. virginiana (including var. demissa and var. melanocarpa) is in fact Po. prunicola. The powdery mildew on Pr. avium is genetically, morphologically, and biologically distinct from Po. prunicola and is described here as the new species Po. cerasi. Cross-inoculation experiments confirmed that these two species are host specific. Podosphaera prunicola was unable to colonize Pr. avium, whereas Po. cerasi was unable to colonize Pr. virginiana. Morphological reexamination of numerous specimens identified as Po. prunicola on a broad range of Prunus species suggests that Po. prunicola is probably confined to species in Prunus subgen.Padus (= Prunus subgen. Cerasus sect. Laurocerasus, including sect. Padus), with Pr. virginiana as the principal host. Podosphaera cerasi occurs on hosts in Prunus subgen. 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. prunicola on Pr. serotina and its widespread occurrence in the United States.

Taxonomy of the Golovinomyces cynoglossi Complex (Erysiphales, Ascomycota) Disentangled by Phylogenetic Analyses and Reassessments of Morphological Traits

The name Golovinomyces cynoglossi s. lat. is traditionally applied to a complex of morphologically similar powdery mildews on hosts of the plant family Boraginaceae. The current species-level taxonomy within this complex is ambiguous due to the lack of phylogenetic examinations. The present study applied phylogenetic methods to clarify the taxonomy of G. cynoglossi s. lat. Phylogenetic analysis of rDNA ITS sequences retrieved from Asian, European and North American specimens revealed that G. cynoglossi s. lat. collections from different hosts involved several species in five clearly separated lineages. Clade I consists primarily of Golovinomyces cynoglossi s. str. on Cynoglossum. Clade III consists of Golovinomyces sequences retrieved from the host genera Symphytum and Pulmonaria. The taxa within clade III are now assigned to G. asperifoliorum comb. nov. Clade V encompasses G. cynoglossi s. lat. on the host genera Bothriospermum, Buglossoides, Echium, Myosotis, and Trigonotis. The taxa within clade V are now assigned to G. asperifolii comb. nov. The species concerned in this study were lecto- and epitypified to stabilize their nomenclature.

Comparative genome analyses reveal sequence features reflecting distinct modes of host-adaptation between dicot and monocot powdery mildew

BACKGROUND

Powdery mildew (PM) is one of the most important and widespread plant diseases caused by biotrophic fungi. Notably, while monocot (grass) PM fungi exhibit high-level of host-specialization, many dicot PM fungi display a broad host range. To understand such distinct modes of host-adaptation, we sequenced the genomes of four dicot PM biotypes belonging to Golovinomyces cichoracearum or Oidium neolycopersici.

RESULTS

We compared genomes of the four dicot PM together with those of Blumeria graminis f.sp. hordei (both DH14 and RACE1 isolates), B. graminis f.sp. tritici, and Erysiphe necator infectious on barley, wheat and grapevine, respectively. We found that despite having a similar gene number (6620-6961), the PM genomes vary from 120 to 222 Mb in size. This high-level of genome size variation is indicative of highly differential transposon activities in the PM genomes. While the total number of genes in any given PM genome is only about half of that in the genomes of closely related ascomycete fungi, most (~ 93%) of the ascomycete core genes (ACGs) can be found in the PM genomes. Yet, 186 ACGs were found absent in at least two of the eight PM genomes, of which 35 are missing in some dicot PM biotypes, but present in the three monocot PM genomes, indicating remarkable, independent and perhaps ongoing gene loss in different PM lineages. Consistent with this, we found that only 4192 (3819 singleton) genes are shared by all the eight PM genomes, the remaining genes are lineage- or biotype-specific. Strikingly, whereas the three monocot PM genomes possess up to 661 genes encoding candidate secreted effector proteins (CSEPs) with families containing up to 38 members, all the five dicot PM fungi have only 116-175 genes encoding CSEPs with limited gene amplification.

CONCLUSIONS

Compared to monocot (grass) PM fungi, dicot PM fungi have a much smaller effectorome. This is consistent with their contrasting modes of host-adaption: while the monocot PM fungi show a high-level of host specialization, which may reflect an advanced host-pathogen arms race, the dicot PM fungi tend to practice polyphagy, which might have lessened selective pressure for escalating an with a particular host.

Powdery mildew of Chrysanthemum × morifolium: phylogeny and taxonomy in the context of Golovinomyces species on Asteraceae hosts

The 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. chrysanthemi was 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. chrysanthemi differs from true G. artemisiae in 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 Golovinomyces to Artemisia and Chrysanthemum species signifies a coevolutionary event between the powdery mildews concerned and their host species in the subtribe Artemisiinae (Asteraceae tribe 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 Anthemideae of the Asteraceae, are epitypified: Alphitomorpha depressa β artemisiae (≡ Alphitomorpha artemisiae), Erysiphe artemisiae, and Oidium chrysanthemi. Erysiphe macrocarpa is 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.

Early evolution of endoparasitic group in powdery mildews: molecular phylogeny suggests missing link between Phyllactinia and Leveillula

Of the 17 genera of the Erysiphaceae, only four genera (viz. Leveillula, Phyllactinia, Pleochaeta and 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/Queirozia group, from which the genus Phyllactinia was derived. Finally, the truly endoparasitic genus Leveillula emerged 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 Leveillula derived from a part of the "Basal Phyllactinia group". However, all sister taxa to Leveillula were distributed in North and South America. Because the putative geographic origin of Leveillula is assumed to be Central and Western Asia or the Mediterranean region, we postulate a missing link during the evolution of Leveillula from 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 bougainvilleae sp. nov., Ph. caricae comb. nov., Ph. caricicola comb. nov., Ph. durantae comb. nov., Ph. leveilluloides sp. nov., Ph. obclavata comb. nov., and Ph. papayae comb. nov.

First comprehensive phylogenetic analysis of the genus Erysiphe (Erysiphales, Erysiphaceae) I. The Microsphaera lineage

The genus Erysiphe (including powdery mildew fungi only known as anamorph, Pseudoidium) is the largest genus in the Erysiphaceae and contains more than 50% of all species in this family. Little is known about the phylogenetic structure of this genus. We conducted a comprehensive phylogenetic analysis of the Microsphaera-lineage, a monophyletic group including species of sects. Microsphaera and Erysiphe, using 401 sequences of nuc ITS1-5.8S-ITS2 and the 28S rDNA regions. This analysis gave many small clades delimited by the host plant genus or family. We identified two deep branches, albeit with moderate bootstrap supports, that divided the 401 sequences into three large groups. In addition, we identified four large clades consisting of homogeneous sequences of powdery mildews from a wide range of host plants beyond family level, namely, the E. aquilegiae clade, the E. alphitoides clade, the E. quercicola clade, and the E. trifoliorum s. lat. clade. Isolates from herbaceous plants were mostly situated in the E. aquilegiae clade and in Group III that was located at the most derived position of the Microsphaera-lineage. On the other hand, the basal part of the Microsphaera-lineage was occupied by isolates from woody plants except for E. glycines that was used as an outgroup taxon. This supports our previous hypothesis that tree-parasitic powdery mildews are phylogenetically primitive in the Erysiphaceae in general, and host-shift from trees to herbs occurred many times independently during the evolution of powdery mildews. Molecular clock analyses suggested that the divergence of the Microsphaera-lineage began ca. 20 million years ago in the Miocene Epoch of the Neogene Period.