Phytophthora pachypleura sp. nov., a new species causing root rot of Aucuba japonica and other ornamentals in the United Kingdom |
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| Authors: | B Henricot A Pérez Sierra T Jung |
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| Institution: | 1. The Royal Horticultural Society, , Wisley, Woking, Surrey, GU23 6QB UK;2. Instituto Agroforestal Mediterráneo, Universidad Politécnica de Valencia (IAMUPV), , 46022 Valencia, Spain;3. Center for Mediterranean Bioresources and Food (MeditBio), Laboratory of Molecular Biotechnology and Phytopathology, University of Algarve – Campus de Gambelas, , 8005‐139 Faro, Portugal;4. Phytophthora Research and Consultancy, , 83098 Brannenburg, Germany |
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| Abstract: | Isolates of an unknown Phytophthora species from the ‘Phytophthora citricola complex’ have been found associated with mortality of Aucuba japonica in the UK. Based on morphological characteristics, growth–temperature relationships, sequences of five DNA regions and pathogenicity assays, the proposed novel species is described as Phytophthora pachypleura. Being homothallic with paragynous antheridia and semipapillate sporangia, P. pachypleura resembles other species in the ‘P. citricola complex’ but can be discriminated by its distinctively thick‐walled oospores with an oospore wall index of 0·71. In the phylogenetic analysis based on three nuclear (ITS, β‐tubulin, EF‐1α) and two mitochondrial (cox1, nadh1) DNA regions, P. pachypleura formed a distinct clade within the ‘P. citricola complex’ with P. citricola s. str., P. citricola E and P. acerina as its closest relatives. Phytophthora pachypleura is more aggressive to A. japonica than P. plurivora and P. multivora and has the potential to affect other ornamental species. |
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| Keywords: | pathogenicity phylogeny
Phytophthora citricola
Phytophthora multivora
Phytophthora plurivora
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