Erysiphe wadae: a new species of Erysiphe sect. Uncinula on Japanese beech

 A new species of Erysiphe sect. Uncinula is described and illustrated from Japan. Erysiphe wadae sp. nov., found on Japanese beech (Fagus crenata, Fagaceae), is characterized by having two types of appendages, i.e., a long (true) appendage arising from the equatorial zone of the ascomata, and a short appendage arising from the upper part of the ascomata. This characteristic is shared by E. simulans, E. australiana, E. flexuosa, E. liquidambaris, E. prunastri, and E. togashiana. Erysiphe wadae differs from the latter five species in its brown-colored appendage. Erysiphe simulans is most similar to E. wadae, but differs in its loosely uncinate appendage and smaller number of ascospores. Identity of the nucleotide sequences of the rDNA ITS region is 92.3% between the two species. The significance of the two types of appendage in taxonomy and phylogeny of powdery mildews is discussed based on molecular phylogenetic analysis. Received: November 8, 2002 / Accepted: January 29, 2003 Acknowledgments We are grateful to Drs. Yukio Harada and Hideki Naito for help in collecting powdery mildew specimens; Dr. Uwe Braun for providing the specimen of E. flexuosa; and Mr. Tetsuya Hirata and Miss Sanae Matsuda for nucleotide sequences of E. togashiana and E. flexuosa. This work was partially supported by a Grant-in-Aid for Scientific Research (No. 13660047) from Ministry of Education, Culture, Sports, Science and Technology, Japan.     

Two new species of Erysiphe sect. Uncinula (Erysiphales): Erysiphe fernandoae and E. michikoae

Two new species of Erysiphe section Uncinula are described and illustrated based on the molecular and morphological analyses: (1) Erysiphe fernandoae sp. nov. on Fernandoa adenophylla is distinct from other Erysiphe species on the plant family Bignoniaceae by having smaller asci, ca 12 appendages per chasmothecium and being found only in Asia; (2) Erysiphe michikoae sp. nov. on Celtis jessoensis differs from Erysiphe kusanoi on other Celtis species in having smaller chasmothecial, ascal and ascospore dimensions, and fewer number of chasmothecium appendages. The phylogenetic relationships of the two new species with other closely related species are discussed based on 28S and ITS rDNA sequences.     

Erysiphe azerbaijanica and E. linderae: Two new powdery mildew species (Erysiphales) belonging to the Microsphaera lineage of Erysiphe

Two new species, Erysiphe azerbaijanica on Castanea sativa and E. linderae on Lindera praecox, both belonging to the Microsphaera lineage of the genus Erysiphe are described based on morphological and molecular data. Erysiphe azerbaijanica is distinguished from other Erysiphe species occurring on Castanea spp. by its cylindrical conidia with a length/width ratio of 2–3.6, longer conidiophore, and foot-cells. Molecular analyses indicated that this species forms a clade of its own, supporting the morphological observations. Molecular phylogenetic analyses showed that E. blasti s. lat. is divided into two genetically differentiated groups associated with different host species. Based on the sequence differences in the 28S rRNA gene and ITS region, connected with differences in the number and length of appendages, the fungus on L. praecox is described as a new species, E. linderae.     

Erysiphe corylopsidis sp. nov., a new powdery mildew fungus found on Corylopsis spicata and C. pauciflora

A powdery mildew fungus occurring on leaves of Corylopsis pauciflora and C. spicata in Japan is described as a new species, Erysiphe corylopsidis. This species is characterized by fewer than 15 appendages on a chasmothecium, primary branches of the appendages occasionally elongated, and a relatively small number (2–5) of ascospores per ascus. Molecular phylogenetic analyses based on rDNA ITS and 28S rDNA sequences indicate that this fungus forms an independent lineage in the genus Erysiphe.     

<Emphasis Type="Italic">Erysiphe monascogera</Emphasis> sp. nov., an unusual powdery mildew fungus found on fruits of <Emphasis Type="Italic">Styrax japonica</Emphasis>

Morphological observations using light and scanning electron microscopes and molecular phylogenetic analysis revealed that the fungus growing on the surface of fruits or sepals of Styrax japonica collected at Nagano, Japan, is a new powdery mildew with an unusual morphology, described here as Erysiphe monascogera. This fungus has mainly a single ascus in a chasmothecium, but molecular phylogenetic analysis and the shape of the hyphal appressoria suggest that it is an Erysiphe species. Erysiphe monascogera is a sister-species to E. nomurae on Symplocos chinensis var. leucocarpa f. pilosa, although there are obvious morphological differences between the two species. This inconsistency between molecular phylogeny and morphology may be explained by the unique habitat of E. monascogera. Erysiphe monascogera and E. nomurae are included in a clade composed of the E. alphitoides complex, which suggests that these two species diverged by host jumping of the E. alphitoides complex, having oaks as major host plants.     

Erysiphe paracarpinicola: A new species of Erysiphe sect. Uncinula on Carpinus cordata (Betulaceae)

A phylogeny of Erysiphe sect. Uncinula on Carpinus spp. was reconstructed using the 28S rDNA sequences and a combined alignment of the 28S, ITS, and IGS rDNA sequences. The analysis was supplemented with morphological data obtained from examination of voucher specimens. A sequence of Erysiphe sect. Uncinula on C. cordata formed a distinct lineage separated from sequences of other Erysiphe species on Carpinus spp., indicating a cryptic species, which is described as E. paracarpinicola. The new species is genetically as well as morphologically most similar to E. carpinicola s. str., but differs in having fewer asci per chasmothecium (mainly 3–5 vs 4–10) and shorter chasmothecial appendages. A key to species of Erysiphe sect. Uncinula on Carpinus spp. is provided.     

Molecular phylogeny reveals the presence of cryptic speciation within Erysiphe japonica (≡ Typhulochaeta japonica), a powdery mildew on Quercus spp.

Molecular phylogenetic analyses based on 28S, ITS and IGS rDNA sequences indicate that Erysiphe japonica (≡ Typhulochaeta japonica) consists of two different genetic groups, one group on Quercus aliena, Q. robur and Q. serrata, and another group on Q. crispula var. crispula and Q. crispula var. horikawae. As morphological difference between the two groups are not yet marked distinctly, we suppose that the process of speciation has not yet been finished and propose a new variety, E. japonica var. crispulae, for the latter group based on the difference in host range and the distinct genetic segregation. Quercus robur (pedunculate oak) is a new host of E. japonica.     

Morphophylogenetic study revealed that Erysiphe gracilis (powdery mildew of evergreen oaks,Erysiphales) is a species complex consisting of six different species

Erysiphe gracilis is a powdery mildew species that occurs on evergreen oak species belonging to Quercus subgen. Cyclobalanopsis in East Asia (China and Japan). In a previous report, we found that E. gracilis var. gracilis is divided into four genotypes each of them forming a separate clade with strong bootstrap support. In this study, we further investigated genotype speciation in E. gracilis var. longissima occurring on Q. acuta and Q. sessilifolia, and found that this variety is also divided into two distinct genotypes. These results suggested that E. gracilis represents a species complex consisting of six different species. Based on detailed morphological examinations correlating with results of molecular sequence analyses, we propose to divide E. gracilis into six species, encompassing three new species (E. uncinuloides, E. pseudogracilis, and E. longiappendiculata), one new name (E. longifilamentosa), and two known species (E. gracilis s. str. and E. hiratae). A key to the species concerned is provided.     

<Emphasis Type="Italic">Erysiphe patagoniaca</Emphasis>: a new species of <Emphasis Type="Italic">Erysiphe </Emphasis>sect. <Emphasis Type="Italic">Uncinula </Emphasis>from Patagonia,Argentina

 A new species of Erysiphe sect. Uncinula is described and illustrated from Patagonia, Argentina. Erysiphe patagoniaca sp. nov., found on leaves of Nothofagus × antarctica, is similar to E. nothofagi and E. kenjiana, but differs in its appendages being twisted throughout their length and the number of appendages, asci, and ascospores. The two endemic species of Erysiphe sect. Uncinula, E. magellanica and E. nothofagi, coexisted on the same leaves together with Erysiphe patagoniaca. Received: September 19, 2002 / Accepted: November 28, 2002 Acknowledgments The authors are grateful to Ms. Seiko Niinomi for providing the micrographs of ascomata of Erysiphe spp. on Nothofagus. Correspondence to:S. Takamatsu     

Two new species of powdery mildew fungi from Japan

The following two new species of powdery mildew fungi were found onStephania cephalantha (Menispermaceae) andViburnum opulus var.calvescens (Caprifoliaceae) in Japan:

1. Erysiphe stephaniae onS. cephalantha has smaller cleistothecia and more asci present in the cleistothecium, which include remarkably larger ascospores, thanErysiphe pisi, which has been previously described on the same host plant from Taiwan.
2. Microsphaera shinanoensis onV. opulus var.calvescens is easily distinguishable fromMicrosphaera alni, hitherto known on this plant, and otherMicrosphaera fungi onViburnum plants by the shape of its appendages and the numbers of its asci and ascospores.

     

New and interesting species ofEmericella from Brazilian soil

Among the ascomycete isolates from soil and armadillo dung collected in São Paulo State, Brazil, a new species ofEmericella, E. montenegroi and a new variety ofE. rugulosa, E. rugulosa var.Iazulina are described and illustrated.Emericella montenegroi differs from the other known species of the genus in having ascospores with an incompletely reticulate or ribbed ornamentation on the convex walls.Emericella rugulosa var.Iazulina differs from the type variety in having blue to violet color of ascospores. Isolations ofE. corrugata andE. foveolata are also reported as a South American record. A synoptic key to all accepted species of the genus is provided.     

Pseudoidium javanicum,a new species of powdery mildew on Acalypha spp. from Indonesia

Pseudoidium javanicum is proposed as a new species based on analyses of 28S, ITS and IGS rDNA sequences, and morphological data. This new species was found on Acalypha wilkesiana var. marginata, A. argentea, and A. cristata collected from Cibodas Botanical Garden, Bogor (West Java Province, Indonesia). Our analyses showed that all these specimens have identical rDNA sequences and similar morphological characteristics. They form a distinct clade separated from other species of Erysiphaceae. Pseudoidium javanicum differs from Erysiphe acalyphae by having shorter conidiophores and foot cells 1–3 times as long as the 0–2 following cells. The conidial size of Ps. javanicum is also smaller than that of E. jatrophae.     

Two Erysiphe species associated with recent outbreak of soybean powdery mildew: results of molecular phylogenetic analysis based on nuclear rDNA sequences

 Serious outbreaks of powdery mildew by a fungus belonging to the mitosporic genus Oidium subgenus Pseudoidium have been reported on soybean (Glycine max) in a wide area of eastern Asia since 1998. The taxonomic and phylogenetic placement of the causal fungus has not yet been determined because of lack of the perfect stage. We found ascomata having mycelioid appendages on a single leaf of soybean infested by powdery mildew. Molecular phylogenetic analysis was conducted based on a total of 14 sequences of the rDNA internal transcribed spacer (ITS) region from 13 soybean and wild soybean (Glycine soja) materials collected in Japan, Korea, Vietnam, and the United States, combined with 47 sequence data obtained from the DNA databases. It was revealed that two Erysiphe species were associated with the outbreak of soybean powdery mildew. There was 16% difference between the two species in genetic divergence of the ITS sequence. One species with perfect stage has an ITS sequence identical to that of Erysiphe glycines on Amphicarpaea and is identified as Erysiphe glycines based on the ITS sequence and morphology of ascomata. The second species, without the perfect stage, is likely to be Erysiphe diffusa (= Microsphaera diffusa), known as the fungus causing soybean powdery mildew in the United States, because the ITS sequences are identical to those from materials collected in the United States. However, we need materials having ascomata of E. diffusa to confirm the species name. Received: March 15, 2002 / Accepted: May 22, 2002     

A new variety ofMyxotrichum ochraceum from Japanese soil

Myxotrichum ochraceum var.frigidum, a new variety ofMyxotrichum, is described and illustrated from the material from Japanese soil. It is morphologically characterized by dull green to black ascomata with a yellow-orange centrum, peridium consisting of a fragile hyphal network, peridial hyphae with internal coiled branches and short spine-like appendages, pale yellow fusiform striate ascospores, and the absence of an anamorph. The new variety primarily differs from the type variety in the absence of elongate appendages. A key to all accepted species of the genus is revised.     

Geographic and temporal distributions of four genotypes found in Erysiphe gracilis var. gracilis,a powdery mildew of evergreen oaks (Erysiphales)

A survey of 402 samples of Erysiphe gracilis var. gracilis on evergreen oaks collected from a wide area of western Japan showed that they were divided into four distinct genotypes each forming a separate clade with high bootstrap support, which were referred to as E. hiratae (genotype I), E. uncinuloides (genotype II), E. gracilis s. str. (genotype III), and E. pseudogracilis (genotype IV) in a separate taxonomic treatment. However, there are no clear differences in geographic distributions among these four genotypes. Quercus myrsinifolia was only infected by genotype II and Q. salicina only by genotype IV, whereas Q. glauca was infected by all four. These results strongly suggest an association between host species and speciation of these genotypes. A further 312 samples of Q. glauca with E. gracilis s. lat. colonies were collected from four locations in the Mie University campus to investigate frequency of genotypes I and II every month from May 2015 to January 2016. No temporal isolation was found in genotype frequencies. These genotypes frequently co-existed on a single leaf surface, especially at the locations disturbed by human activities. Two oak powdery mildews, E. gracilis s. lat. and Cystotheca wrightii, produced conidia only one month a year and their life cycle differed from most other powdery mildew species. This suggests that these oak mildews developed their unique life cycles to synchronize with the life cycle of evergreen oaks.     

Intraspecies differentiation in the powdery mildew Erysiphe cichoracearum determined with rDNA RFLPs

The powdery mildew species Erysiphe cichoracearum has a described host range of over 300 plant species from among several families. Host-range testing indicates host-specialized subdivision within this taxonomic species. However, the extent of subdivision remains largely undetermined among host-limited forms. We have characterized diversity among field collections of E. cichoracearum from a variety of hosts, and from other powdery mildew species, with RFLPs from a PCR amplified ribosomal DNA (rDNA) segment The E. cichoracearum samples expressed six distinct RFLP haplotypes. Each haplotype was specific to either a single host or to a set of related host species. These haplotypes formed a continuum of divergence ranging from about 18–35% average pairwise distance from one another, while those from other mildew species clustered at consistently higher average pairwise distances from E. cichoracearum and from each other. Our findings support earlier suggestions, based on host-range and morphological characterizations, that E. cichoracearum is a complex of morphologically similar, but host-limited forms. Also, comparisons of rDNA haplotype distance between E. cichoracearum and Blumeria (Erysiphe) graminis were consistently greater than between E. cichoracearum and Sphaerotheca fulginea. This result supports earlier questions concerning the monophyletic nature of Erysiphe.     

<Emphasis Type="Italic">Erysiphe fimbriata</Emphasis> sp. nov.: a powdery mildew fungus found on <Emphasis Type="Italic">Carpinus laxiflora</Emphasis>

Ascomata of a powdery mildew-like fungus have been found on Carpinus laxiflora in Tochigi Prefecture of Japan since 2003. The morphological and molecular characteristics of this fungus are reported, and a new species, Erysiphe fimbriata, is proposed. It has large chasmothecia (200–250 μm in diameter) with long (up to 4–5 mm in length), fimbriate appendages arising from the upper half of the chasmothecia and turning upward, and numerous asci (22–38 per chasmothecium). Erysiphe fimbriata is a unique fungus both genetically and morphologically.