The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Xiu-guo Zhang - One of the best experts on this subject based on the ideXlab platform.
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Three novel species of Stemphylium from Sinkiang, China: their morphological and molecular characterization
Mycological Progress, 2010Co-Authors: Yun-fei Pei, Yong Wang, Yun Geng, Nichole R. O'neill, Xiu-guo ZhangAbstract:Three new species of Stemphylium were isolated from diseased leaves of Luffa cylindrica, Lycium chinense and Cucumis melo growing in the Sinkiang province of Northwest China. Stemphylium luffae, S. lycii and S. cucumis are described by morphological and molecular phylogenetic analyses. The principal morphological characteristics of these three species are congruent with those of Stemphylium. They are distinguished from morphologically similar Stemphylium species based on characteristics of their conidia and conidiophores. In order to establish the molecular phylogenetic status of these species, DNA loci including the internal transcribed spacer (ITS) nuclear rDNA region and the glyceraldehyde-3-phosphate dehydrogenase (gpd) genes were amplified and sequenced. Phylogenetic analyses using Maximum-Parsimony (MP) and Neighbor-Joining (NJ) were performed on the combined DNA sequences of ITS and gpd gene regions. Both morphological observations and molecular analyses support S. luffae, S. lycii and S. cucumis as three new taxa.
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Molecular and morphological description of two new species of Stemphylium from China and France.
Mycologia, 2010Co-Authors: Yong Wang, Yun Geng, Yun-fei Pei, Xiu-guo ZhangAbstract:Two new species of Stemphylium (anamorphic Pleospora) are described on the basis of morphological characters and molecular phylogenetic analyses. Stemphylium phaseolina and S. variabilis were isola...
Yun-fei Pei - One of the best experts on this subject based on the ideXlab platform.
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Three novel species of Stemphylium from Sinkiang, China: their morphological and molecular characterization
Mycological Progress, 2010Co-Authors: Yun-fei Pei, Yong Wang, Yun Geng, Nichole R. O'neill, Xiu-guo ZhangAbstract:Three new species of Stemphylium were isolated from diseased leaves of Luffa cylindrica, Lycium chinense and Cucumis melo growing in the Sinkiang province of Northwest China. Stemphylium luffae, S. lycii and S. cucumis are described by morphological and molecular phylogenetic analyses. The principal morphological characteristics of these three species are congruent with those of Stemphylium. They are distinguished from morphologically similar Stemphylium species based on characteristics of their conidia and conidiophores. In order to establish the molecular phylogenetic status of these species, DNA loci including the internal transcribed spacer (ITS) nuclear rDNA region and the glyceraldehyde-3-phosphate dehydrogenase (gpd) genes were amplified and sequenced. Phylogenetic analyses using Maximum-Parsimony (MP) and Neighbor-Joining (NJ) were performed on the combined DNA sequences of ITS and gpd gene regions. Both morphological observations and molecular analyses support S. luffae, S. lycii and S. cucumis as three new taxa.
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Molecular and morphological description of two new species of Stemphylium from China and France.
Mycologia, 2010Co-Authors: Yong Wang, Yun Geng, Yun-fei Pei, Xiu-guo ZhangAbstract:Two new species of Stemphylium (anamorphic Pleospora) are described on the basis of morphological characters and molecular phylogenetic analyses. Stemphylium phaseolina and S. variabilis were isola...
Barry M Pryor - One of the best experts on this subject based on the ideXlab platform.
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Molecular characterization of Embellisia and Nimbya species and their relationship to Alternaria, Ulocladium and Stemphylium.
Mycologia, 2003Co-Authors: Barry M Pryor, D. M. BigelowAbstract:DNA sequences from rDNA and protein- coding regions were determined for six Embellisia and two Nimbya spp. and were compared to those from Alternaria, Ulocladium and Stemphylium spp. Se- quences determined included rDNA from the nucle- ar internal transcribed-spacer region (ITS1/5.8S/ ITS2) and the mitochondrial small-subunit (mt SSU) and a portion of the glyceraldehyde-3-phosphate de- hydrogenase (gpd) gene. Phylogenetic analyses were performed on each dataset separately and then com- bined for total evidence analysis using methods of maximum parsimony and maximum likelihood. Re- sults revealed that Embellisia and Nimbya clustered within a large monophyletic Alternaria-Nimbya-Embel- lisia-Ulocladium clade with Stemphylium as the sister taxon. Members of the infectoria species-group were the most basal group in this large polygeneric clade. Embellisia and Nimbya were sister taxa of the remain- ing Alternaria and Ulocladium spp. and were related more closely to Alternaria than was Stemphylium. Four Embellisia spp. formed a monophyletic clade. How- ever, E. allii clustered with the two Nimbya spp. and E. indefessa clustered with Alternaria and Ulocladium spp., revealing that Embellisia, as currently circum- scribed, is polyphyletic. Potential revisions of taxon- omy for all genera are discussed.
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molecular phylogenetic relationships amongst alternaria species and related fungi based upon analysis of nuclear its and mt ssu rdna sequences
Fungal Biology, 2000Co-Authors: Barry M Pryor, R L GilbertsonAbstract:To elucidate relationships among Alternaria, Ulocladium, and Stemphylium species, nuclear internal transcribed spacer (ITS) and mitochondrial small subunit (SSU) ribosomal DNA (rDNA) sequences from 18 Alternaria, four Ulocladium and four Stemphylium spp. were determined and compared. Phylogenetic analysis of the ITS and SSU rDNA sequences, performed by the neighbour joining and maximum parsimony methods, revealed that the Stemphylium spp. were phylogenetically distinct from the Alternaria and Ulocladium spp. Most Alternaria spp. and the Ulocladium spp. were placed together in a large Alternaria/Ulocladium clade. Within this large clade, the Alternaria spp. clustered into several distinct species-clades, most of which correlated with species-groups previously established based upon morphological characteristics. The Ulocladium spp. were placed into two species-clades, each of which also included Alternaria spp. A. longissima was distantly related to the other Alternaria spp., as well as the Ulocladium and Stemphylium spp. Based upon ITS and nuclear 18S rDNA sequence identities, A. longissima was most closely related to Leptosphaeria.
Yong Wang - One of the best experts on this subject based on the ideXlab platform.
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Three novel species of Stemphylium from Sinkiang, China: their morphological and molecular characterization
Mycological Progress, 2010Co-Authors: Yun-fei Pei, Yong Wang, Yun Geng, Nichole R. O'neill, Xiu-guo ZhangAbstract:Three new species of Stemphylium were isolated from diseased leaves of Luffa cylindrica, Lycium chinense and Cucumis melo growing in the Sinkiang province of Northwest China. Stemphylium luffae, S. lycii and S. cucumis are described by morphological and molecular phylogenetic analyses. The principal morphological characteristics of these three species are congruent with those of Stemphylium. They are distinguished from morphologically similar Stemphylium species based on characteristics of their conidia and conidiophores. In order to establish the molecular phylogenetic status of these species, DNA loci including the internal transcribed spacer (ITS) nuclear rDNA region and the glyceraldehyde-3-phosphate dehydrogenase (gpd) genes were amplified and sequenced. Phylogenetic analyses using Maximum-Parsimony (MP) and Neighbor-Joining (NJ) were performed on the combined DNA sequences of ITS and gpd gene regions. Both morphological observations and molecular analyses support S. luffae, S. lycii and S. cucumis as three new taxa.
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Molecular and morphological description of two new species of Stemphylium from China and France.
Mycologia, 2010Co-Authors: Yong Wang, Yun Geng, Yun-fei Pei, Xiu-guo ZhangAbstract:Two new species of Stemphylium (anamorphic Pleospora) are described on the basis of morphological characters and molecular phylogenetic analyses. Stemphylium phaseolina and S. variabilis were isola...
Mary Ruth Mcdonald - One of the best experts on this subject based on the ideXlab platform.
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Risk assessment of secondary metabolites produced by fungi in the genus Stemphylium.
Canadian journal of microbiology, 2021Co-Authors: Sara M. Stricker, Bruce D. Gossen, Mary Ruth McdonaldAbstract:The fungal genus Stemphylium (phylum Ascomycota, teleomorph Pleospora) includes plant pathogenic, endophytic, and saprophytic species with worldwide distributions. Stemphylium spp. produce prodigious numbers of air-borne spores, so are a human health concern as allergens. Some species also produce secondary metabolites such as glucosides, ferric chelates, aromatic polyketides, and others that function as toxins that damage plants and other fungal species. Some of these compounds also exhibit a low level of mammalian toxicity. The high production of air-borne spores by this genus can result in a high incidence of human exposure. Concern about toxin production appears to be the reason that S. vesicarium, which is a pathogen of several vegetable crops, was classified in Canada as a potential risk of harm to humans for many years. A detailed assessment of the risk of exposure was provided to the relevant regulatory body, Public Health Agency of Canada. They determined that Stemphylium spp., in nature or under laboratory conditions, posed little to no risk to humans or animals, and the species was re-assigned as a basic (level 1) risk agent.
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Fungicide efficacy and timing for the management of Stemphylium vesicarium on onion
Canadian Journal of Plant Pathology, 2020Co-Authors: Sara M. Stricker, Cyril Selasi Tayviah, Bruce D. Gossen, Mary Ruth McdonaldAbstract:Stemphylium leaf blight (SLB), caused by Stemphylium vesicarium (Wallr.) E.G. Simmons, has become an important disease of onion (Allium cepa L.) in Ontario, Canada, and the northeastern USA in rece...
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Susceptibility to Stemphylium vesicarium of asparagus, onion, pear, and rye in Canada
Canadian Journal of Plant Pathology, 2019Co-Authors: Jennifer Foster, Sara M. Stricker, Bruce D. Gossen, C. Selasi Tayviah, Mary Ruth McdonaldAbstract:Diseases caused by Stemphylium vesicarium are an increasing problem in the major asparagus and onion production regions of eastern and central Canada. Replicated and repeated controlled environment...
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Evaluation of the TOM-CAST Forecasting Model in Asparagus for Management of Stemphylium Leaf Spot in Ontario, Canada.
Plant disease, 2018Co-Authors: Jennifer Foster, Mary Ruth McdonaldAbstract:In the last 5 years, asparagus acreage in Canada has increased by over 25%. Stemphylium leaf spot, caused by Stemphylium vesicarium, has emerged as the predominant foliar pathogen of asparagus. Typically, contact fungicides are applied every 14 days; however, regardless of the number of applications, growers are not achieving adequate control of the disease. The TOM-CAST forecasting model is used widely in Michigan asparagus fields, but it has never been assessed for suitability in Ontario or in the popular cultivar, Guelph Millennium. Six field trials were conducted in 2012 and 2013 to evaluate the TOM-CAST forecasting model in two asparagus cultivars. The fungicides chlorothalonil or azoxystrobin/difenoconazole were applied according to the forecasting model or on a 14-day interval. The effectiveness of the forecasting model differed between sites and cultivars. Even though TOM-CAST is used in all cultivars in Michigan, TOM-CAST was not effective on Guelph Millennium. In the cultivar Jersey Giant, however, TOM-CAST with a 20 disease severity value spray interval improved control of Stemphylium leaf spot without increasing the number of sprays, compared with a 14-day treatment. The results in Guelph Millennium differed between sites. At one site, TOM-CAST maintained similar levels of Stemphylium leaf spot, but increased the number of applications, compared with a 14-day application interval. Of more concern, none of the fungicide treatments differed greatly from the untreated control at the other site. Our results show that forecasting models need to be validated locally in asparagus cultivars relevant to production today.
