Phytophthora multivora: another new species of Phytophthora
In Australia, in the south-west part of Western Australia, decline and tree mortality have been observed in forests on Eucalyptus gomphocephala and E. marginata (Myrtaceae) since the 1990s, and since 2006 on Agonis flexuosa (Myrtaceae). In May and June 2007, Phytophthora isolates were recovered from the rhizospheres of declining trees (E. gomphocephala, E. marginata, A. flexuosa) in the Yalgorup National Park (south of Perth). Due to their unique morphological, physiological and molecular (ITS, cox1 sequences) characteristics, these isolates were described as a new species called Phytophthora multivora sp. nov. This new species was also detected on E. marginata, Banksia menziesii and B. grandis in other locations (Jarrahdale, Wanneroo, and Pemberton, respectively) in the south-west of Western Australia. Investigations also showed that many isolates collected from a wide range of hosts in Western Australia which had been identified as Phytophthora citricola should be reassigned to P. multivora. This new Phytophthora species was also recovered from soil and root samples that had been collected beneath Phytophthora-sensitive species over the last 30 years in Western Australia, thus expanding the host range of P. multivora to many woody plants: Banksia attenuata, B. grandis, B. littoralis, B. menziesii, B. prionotes, Conospermum sp., Leucopogon verticillatus, Xanthorrhoea gracilis, Podocarpus drouyniana, Patersonia sp., Bossiaea sp., Gastrolobium spinosum and Pinus radiata. It is therefore considered that P. multivora is widespread in Western-Australia (mainly the south-west). In addition, it has been found that 11 ITS sequences deposited in GenBank and designated as P. citricola were identical to P. multivora. Seven of the sequences came from unpublished studies on isolates originating from Canada, Japan, Korea, Hungary, Spain (isolates from ornamental nurseries), and Switzerland, suggesting that P. multivora might also occur in these countries (although this assumption would need confirmation).
Sources
Scott PM, Burgess TI, Barber PA, Shearer BL, Stukely MJC, Hardy GES, Jung T (2009) Phytophthora multivora sp. nov., a new species recovered from declining Eucalyptus, Banksia, Agonis and other plant species in Western Australia. Persoonia 22, 1-13.