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Taxonomic studies in the genus Erysiphe I. Generic delimitation and position in the system of the Erysiphaceae
... It has a polycyclic life cycle with very short incubation and latent periods. The Erysiphe taxonomic studies have been elaborated by Braun (1981Braun ( , 1987Braun ( , 2012. Conidial morphology and germination have been utilized for constructing the identification keys for different powdery mildew genera and species. ...
... Conidial morphology and germination have been utilized for constructing the identification keys for different powdery mildew genera and species. Globally, more than 873 species of PM affecting as many as 10,000 plant species have been documented (Braun 1981(Braun , 1987(Braun , 2012Kuhn et al. 2016). Despite being the presence of both asexual and sexual modes of reproduction, the pathogen variability has not been extensively evaluated for powdery mildew. ...
Brassica napus, rapeseed or oilseed rape, is the major oilseed Brassica crop originated from multiple hybridization events among Brassica rapa and Brassica oleracea. However, its production has been reduced drastically by various biotic factors. These biotic stresses affect growth and development of the plants resulting in huge reduction in oilseed production at global level. Moreover, the control measures are considerably broader in case of diseases than in insect-pest, resulting in more confrontation from the latter. The development of resistant varieties that can survive under stress conditions is of utmost importance. Various management tools like crop rotation and use of resistant varieties etc. are unsuccessful in most of the cases, as insect control measure mostly depends on use of chemicals/insecticides. The information regarding different molecular and cellular mechanisms is essential to understand the biotic stress tolerance in rapeseed. Thus, the use of genetic or genomics information and microarray tools is vital to speed up the productivity potential in genetic improvement programs. The advancement in genomic techniques as well as availability of genome sequences offer opportunities to produce new plant genotype for any particular character. The identification of various genes and/or effectors against various diseases/pests in rapeseed through omics has opened up the way for more studies to depict the host–pathogen interactions and to characterize the gene function and expression. In this context, this chapter provides up-to-date information on the various biotic stresses faced by the crop across the globe, progress made through conventional plant breeding techniques, genomics, bioinformatics, transgenics and genome editing approaches with a particular focus on the trait mapping and molecular marker assisted breeding approaches. The chapter also offers an overview of the latest genomic findings and tools, such as omics that have been widely employed to unravel the genomic and molecular intricacies against various biotic stresses and its potential applications for further rapeseed improvement. So, the combination of classical genetics, genome editing and integrated omics can accelerate rapeseed production globally.KeywordsBrassica napus L.Biotic stressClassical geneticsGene mappingTransgenics and genome editing
... It has a polycyclic life cycle with very short incubation and latent periods. The Erysiphe taxonomic studies have been elaborated by Braun (1981Braun ( , 1987Braun ( , 2012. Conidial morphology and germination have been utilized for constructing the identification keys for different powdery mildew genera and species. ...
... Conidial morphology and germination have been utilized for constructing the identification keys for different powdery mildew genera and species. Globally, more than 873 species of PM affecting as many as 10,000 plant species have been documented (Braun 1981(Braun , 1987(Braun , 2012Kuhn et al. 2016). Despite being the presence of both asexual and sexual modes of reproduction, the pathogen variability has not been extensively evaluated for powdery mildew. ...
Oilseed Brassicas (mainly Brassica napus and Brassica juncea) are economically important crops, cultivated worldwide for their edible oil and protein-rich livestock feed. Major diseases of Brassica crops such as Alternaria leaf spot, white rust, blackleg, Sclerotinia stem rot, clubroot, downy mildew, and powdery mildew results in significant yield and economic losses in Brassica growing countries the world over. The frequency and severity of biotic stresses have intensified due to global climate change which requires urgent research efforts to tackle them effectively. For providing resistance against diseases, genetic resources are being exploited using conventional and tissue culture techniques (embryo rescue and somatic hybridization). Advanced sequencing technologies enabled the sequencing of all the six species of U triangle i.e B. rapa, B. nigra, B. oleracea, B. napus, B. juncea, and B. carinata. The emerging omics technologies such as genomics, proteomics, transcriptomics, and metabolomics have elucidated the function of genes and molecular intricacies between the host and pathogen at a deeper level. In this chapter, we discuss the genetic resources, mapping, and cloning of R-genes, omics approaches, transgenics, gene editing, and bioinformatics tools in context to biotic stresses in rapeseed-mustard. A holistic approach involving genetics, genomics resources, genetic engineering, gene editing, and bioinformatics tools will facilitate the development of Brassica crops which can combat various biotic stresses.
... It has a polycyclic life cycle with very short incubation and latent periods. The Erysiphe taxonomic studies have been elaborated by Braun (1981Braun ( , 1987Braun ( , 2012. Conidial morphology and germination have been utilized for constructing the identification keys for different powdery mildew genera and species. ...
... Conidial morphology and germination have been utilized for constructing the identification keys for different powdery mildew genera and species. Globally, more than 873 species of PM affecting as many as 10,000 plant species have been documented (Braun 1981(Braun , 1987(Braun , 2012Kuhn et al. 2016). Despite being the presence of both asexual and sexual modes of reproduction, the pathogen variability has not been extensively evaluated for powdery mildew. ...
... Arnaud (1921) and Katumoto (1973) regarded the endoparasitic genus Leveillula as primitive and all the ectoparasitic genera derivatives from it. On the other hand Raymond (1927), Blumer (1933) and Braun (1987) argued that the ectoparasitic habit of Leveillula was a xerophytic adaptation and not a primitive feature. The three endoparasitic genera form a monophyletic clade in this study, suggesting that the presence of internal mycelia is a synapomorphic character for these genera, which were derived from ectoparasitic genera by a single event. ...
... They reported that the mycelioid appendage, which long has been regarded as a primitive character (e.g. Blumer 1933, Braun 1981, is a derived character of recent origin. They suggested that the development of mycelioid appendages convergently occurred many times in the respective lineages along with host expansion of the Erysiphales from trees to herbs. ...
Phylogenetic relationships of one of the largest nonlichen-forming ascomycetous groups, the Leotiomycetes, were inferred from genes encoding three rDNA regions (SSU+LSU+5.8S rDNA). A dataset was prepared with rDNA sequences data from 108 isolates, among which we sampled 85 taxa representing four orders and 16 families in the Leotiomycetes. Equally weighted parsimony and Bayesian analyses were performed. Bootstrap proportion and Bayesian posterior probability under the GTR+Γ+I model were estimated along the branches. Based on our results the Leotiomycetes is relatively well defined as a class and it includes the Cyttariales, Erysiphales, Helotiales, Rhytismatales and two families of uncertain position, Myxotrichaceae and Pseudeurotiaceae. The placements of the Thelebolales and Ascocorticiaceae are not examined and are accepted as tentative in the Leotiomycetes. Our results agree with previous studies to remove the Geoglossaceae, including Geoglossum, Trichoglossum and Sarcoleotia, from the Leotiomycetes. Positions of the Erysiphales and Rhytismatales in the Leotiomycetes are confirmed. The Helotiales and Myxotrichaceae are paraphyletic. Close relationships are supported strongly among the Hemiphacidiaceae, Rutstroemiaceae and Sclerotiniaceae, among Loramycetaceae, the northern hemisphere Vibrisseaceae, the Dark Septate Endophyte fungus Phialocephala fortinii and Mollisia cinerea, and between species of Bulgaria and Phadidiopycnis. Sequence data of rDNA regions are not adequate to resolve the relationships among major groups of the Leotiomycetes.
... & Pirnia (Darsaraei et al. 2022), which are segregations of E. pisi s. lat. E. cruchetiana S. Blumer was originally introduced by Blumer (1933) as a separate species and afterwards assigned to E. pisi as morphological variety (Braun 1981). E. pisi var. ...
Fabaceae, one of the largest flowering plant families, comprises several subfamilies and genera. Fabaceous plant species host a large number of powdery mildew species belonging to the genus Erysiphe. The affiliation of these species to Erysiphe is readily possible, but they represent a morphologically and taxonomically complicated complex of closely related, morphologically similar species with overlapping traits. Precise morphological examinations along with phylogenetic analyses, including type collections and other representative samples, are needed to solve the complexity of Erysiphe spp. on legumes. In this study, we sequenced a number of collections of powdery mildews on Pisum, Lathyrus, Vicia and Ononis spp., with a special focus on specimens from Iran, to clarify species delimitations within the Erysiphe pisi complex and other Erysiphe species complexes on legumes. Sequences retrieved from powdery mildew on Pisum and Ononis fall into separate, well supported clades. Hence, the original status of E. cruchetiana as a species of its own on Ononis spp. is reinstated instead of E. pisi var. cruchetiana. Ten species, viz., E. astragali, E. bremeri, E. caulicola, E. cruchetiana, E. iranica, E. medicaginis, E. pisi, E. rayssiae, E. sesbaniae and E. trifoliorum were confirmed for Iran, redescribed and illustrated on the basis of Iranian collections. Erysiphe astragali, E. bremeri, E. coluteae and E. crispula form a genetically little differentiated clade in ITS/LSU analyses, which is referred to as E. astragali clade (complex), comparable to the E. trifoliorum clade (complex). Based on our results, E. coluteae and E. crispula are reduced to synonymy with E. astragali and E. sophorae is considered a synonym of E. bremeri. Sequences of the North American E. intermedia on Lupinus species form a small clade nested within the big E. astragali clade. DNA of the holotype of E. sesbaniae was sequenced for the first time in this study. To use the sequences obtained from some new collections as reference sequences for phylogenetic-taxonomic purposes, we propose, for the interim, reference sequences for E. bremeri, E. caulicola, E. cruchetiana, E. pisi and E. viciae-unijugae.
... In earlier treatments, life history traits and those traits of the assimilative and conidial phase did not play a role. Based on a combination of lobate hyphal appressoria, conidia formed in genuine chains, and asci that develop ascospores only after overwintering, Braun (1981) introduced Erysiphe sect. Galeopsidis (type species: Erysiphe galeopsidis). ...
The second contribution to a new series devoted to the phylogeny and taxonomy of powdery mildews is presented. An overview of Neoerysiphe species is given, including references to ex-type sequences or, if unavailable, representative reference sequences for phylogenetic-taxonomic purposes are provided. The new species N. stachydis is described, and Striatoidium jaborosae is reduced to synonymy with Neoerysiphe macquii. Epitypes with ex-epitype sequences are designated for Alphitomorpha ballotae, A. labiatarum, Erysiphe galii, E. chelones, and E. galeopsidis. Based on phylogenetic analyses, it has been demonstrated that Neoerysiphe cumminsiana is confined to its type host, Roldana hartwegii (= Senecio seemannii), and other North and South American parasites on Asteraceae hosts, previously assigned to this species, pertain to N. macquii. The first record of N. macquii from Europe (Germany) on cultivated Bidens aurea was confirmed by sequencing. Sequence analysis of type material of N. rubiae reveals that this species should be excluded from Neoerysiphe; however, the true affinity of this taxon is not yet clear.
... These genera share a common asexual morph characterized by catenate conidia without distinct fibrosin bodies (Braun 1999). Neoerysiphe is characterized by lobed appressoria and the striate surface of the conidia (Braun 1981;Cook et al. 1997;Braun and Cook 2012). Braun and Cook (2012) mentioned that 15 species of Neoerysiphe are described on different hosts belonging to 11 plant families. ...
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.
... Furthermore, the shorter appendages of E. bulbouncinula are not penicillate, as in Phyllactinia, but capitate (Zheng & Chen, 1979;Zheng & Yu, 1987). On account of the bulbous appendages, Zheng and Chen (1979) Uncinula (Braun, 1981), which was later reduced to synonymy with ...
Erysiphe bulbouncinula (≡ Bulbouncinula bulbosa ) on Koelreuteria paniculata is a powdery mildew native and endemic in China. Fresh samples of this species were collected on K. paniculata in Sichuan Province, China, in 2018. This is the fourth confirmed identification of this species. The original description in 1932 was based on one specimen from Hangzhou and then was described in Nanjing in 1990 and in Taiwan in 1993. The morphology of the new collections of this species is described and illustrated in detail, and agrees well with the original description of the type specimen except for the number of asci (8–16 asci per chasmothecia versus 7–9 asci in the type specimen). To explore the phylogenetic position of this poorly known species, three separate phylogenetic analyses, using partial 28S rDNA and the combination of internal transcribed spacer (ITS) and 28S rDNA sequences, were conducted. The results clearly showed that E. bulbouncinula form a monophyletic clade with strong bootstrap (BS) support (MP = 100%) constituting a sister clade to E. gracilis s. lat., form a subclade with Erysiphe sect. Californiomyces and then form a big group with sect. Typhulochaeta and sect. Uncinula . Phylogenetic results confirm that E. bulbouncinula is more closely allied to Erysiphe than to Phyllactinia . Thus, this species can be maintained in Erysiphe in its current circumscription, confirming Bulbouncinula as a synonym of Erysiphe .
... Neoerysiphe (Braun 1999) is a genus of Erysiphales characterized by the production of conidia in chains, lobed appressoria, the striated surface of conidia, and the maturation of ascospores after hibernation (Braun 1981;Cook et al. 1997;Braun and Cook 2012). A total of 15 species of Neoerysiphe have been described on hosts belonging to 11 plant families (Braun and Cook 2012). ...
A novel species of powdery mildew, Neoerysiphe sechii sp. nov., has been proposed based on host, morphological characteristics, and gene sequences. The new species was found on chayote (Sechium edule) and a wild species, chayotillo (S. mexicanum), in Veracruz, Mexico. This novel species was identified as a member of Neoerysiphe, based on the morphological characteristics of the anamorph: catenescent conidia, lobed appressoria, and Striatoidium-type conidia. No teleomorph was observed. Neoerysiphe sechii is distinguished by foot cells that are frequently cylindrical with a slight widening at the base, a feature not observed previously in other species in the genus. An Erysiphales-specific primer was designed for the 5′ end of the ITS region of the nuclear rDNA. Independent and concatenated phylogenetic analyses with our rDNA sequences and sequences available in GenBank for Neoerysiphe spp. confirmed that the powdery mildew specimens found in Sechium spp. form an independent and strongly supported lineage. This is the first report of a Neoerysiphe species causing powdery mildew on members of Cucurbitaceae, and it is the second species reported from Mexico after N. cumminsiana. Neoerysiphe sechii is found on cultivated and endemic hosts in Mexico, suggesting that the fungus itself may be endemic.
This 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 Erysiphe is too large to be assessed in a single paper; thus, the treatment of Erysiphe is split into three parts, according to phylogenetic lineages. The first paper, presented here, discusses the most basal lineage of Erysiphe and its relationship to allied basal genera within tribe Erysipheae (i.e., Brasiliomyces and 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 Salmonomyces as 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 Erysiphe species of sect. Uncinula but also includes some species that morphologically align with sect. Erysiphe, as well as species that had previously been assigned to Californiomyces and Typhulochaeta. Numerous sequences of Erysiphe species 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. geniculata var. carpinicola. The new species Erysiphe canariensis is described, and the new names E. hosagoudarii and E. pseudoprunastri and the new combination E. ampelopsidis are introduced. ARTICLE HISTORY
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