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Phytophthora obscura sp. nov., a new species of the novel Phytophthora subclade 8d
Author(s) -
Grünwald N. J.,
Werres S.,
Goss E. M.,
Taylor C. R.,
Fieland V. J.
Publication year - 2012
Publication title -
plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.928
H-Index - 85
eISSN - 1365-3059
pISSN - 0032-0862
DOI - 10.1111/j.1365-3059.2011.02538.x
Subject(s) - biology , subclade , antheridium , phytophthora , sporangium , botany , homothallism , phylogenetic tree , clade , gene , spore , genetics , mating type
A new Phytophthora species was detected (i) in the USA, infecting foliage of Kalmia latifolia , (ii) in substrate underneath Pieris , and (iii) in Germany in soil samples underneath Aesculus hippocastanum showing disease symptoms. The new species Phytophthora obscura sp. nov. is formally named based on phylogenetic analysis, host range, Koch’s postulates and morphology. Phytophthora obscura is homothallic with paragynous antheridia and semipapillate sporangia. It is genetically closely related to P. syringae and P. austrocedrae and together these three species define a new Phytophthora subclade 8d, with significant support for all genetic loci analysed including seven nuclear genes and the mitochondrial gene coxII . The morphological and ecological characteristics are very similar to P. syringae , and it is likely that P. obscura was not described earlier because it was identified as P. syringae . Artificial inoculations indicated that horse chestnut, kalmia, pieris and rhododendron might be hosts, and Koch’s postulates were confirmed for kalmia from which it was isolated. This pathogen was named after its elusive nature since it has to date rarely been detected in the US and Germany.