Pythium recalcitrans sp. nov. revealed by multigene phylogenetic analysis
Date
2008
Authors
Moralejo E.
Clemente A.
Descals E.
Belbahri L.
Calmin G.
Lefort F.
Spies C.F.J.
McLeod A.
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Abstract
A new species of Pythium collected from grapevine roots (Vitis vinifera) in South Africa and roots of common beet (Beta vulgaris) in Majorca, Spain, is described. The phylogenetic position of the new species was investigated by multigene sequence analyses of the internal transcribed spacers (ITS1 and ITS2) of the rDNA region, as well as three other nuclear and three mitochondrial coding genes. Maximum likelihood phylogenetic analyses based on ITS rDNA and concatenated β-tubulin and cytrochrome c oxidase II alignment place Pythium recalcitrans together with P. sylvaticum and P. intermedium. Pythium recalcitrans sp. nov. is morphologically almost indistinguishable from other Pythium species that only form hyphal swellings in culture. However its species status is justified by the distinc-tiveness of the DNA sequences in all the genes examined. In culture P. recalcitrans exhibits fast radial growth, abundant spherical to subglobose hyphal swellings but produces no zoosporangia. Sexual structures are not seen in agar media but form in autoclaved grass blades floated on water. Multiple antheridia (1-7) are encountered with most of them diclinous and crook-necked. Oospores are thin-walled and either aplerotic or plerotic. P. recalcitrans was pathogenic to seedlings of Beta vulgaris and Solanum lycopersicum. © 2008 by The Mycological Society of America.
Description
Keywords
fungus, genetic analysis, growth, morphology, new species, pathogen, phylogeny, sugar beet, taxonomy, vine, Africa, Balearic Islands, Eurasia, Europe, Majorca, Mediterranean Sea, South Africa, Southern Africa, Southern Europe, Spain, Sub-Saharan Africa, Beta vulgaris, Beta vulgaris subsp. vulgaris, Lycopersicon esculentum, Oomycetes, Pythium, Pythium intermedium, Pythium sylvaticum, Solanum, Vitaceae, Vitis, Vitis vinifera, ribosomal spacer DNA, article, classification, cytology, fungal gene, genetics, grape, growth, development and aging, microbiology, molecular genetics, phylogeny, Pythium, DNA, Ribosomal Spacer, Genes, Fungal, Molecular Sequence Data, Phylogeny, Pythium, Vitis
Citation
Mycologia
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100
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