A taxonomic re‐evaluation reveals that Phytophthora cinnamomi and P. cinnamomi var. parvispora are separate species. Issue 1 (12th July 2013)

• Record Type: Journal Article
• Authors: Scanu, B.; Hunter, G. C.; Linaldeddu, B. T.; Franceschini, A.; Maddau, L.; Jung, T.; Denman, S.; Andrea, V.
• Is Part Of: Forest pathology. Volume 44:Issue 1(2014:Feb.)
• Page Start: 1
• Page End: 20
• Publication Date: 2013-07-12
• Subjects: Trees -- Diseases and pests -- Periodicals; Trees -- Effect of air pollution on -- Periodicals; Forests and forestry -- Environmental aspects -- Periodicals; 634.9
• DOI: 10.1111/efp.12064
• Languages: English
• ISSNs: 1437-4781

Abstract

<abstract abstract-type="main" id="efp12064-abs-0001"> <title>Summary</title> <p>Between 2008 and 2011, severe dieback associated with root and collar rot was reported on <italic>Arbutus unedo</italic> in several sites in Sardinia, Italy. Isolations from infected tissues and rhizosphere soil samples consistently yielded a <italic>Phytophthora</italic> species. It was initially identified as <italic>Phytophthora cinnamomi</italic> var. <italic>parvispora </italic>Kröber and Marwitz by comparing morphological features with the original description and the internal transcribed spacer (ITS) sequences with those present in GenBank. A multigene phylogeny based on DNA sequence data from two nuclear (ITS and β‐tubulin) and two mitochondrial (<italic>cox</italic>1 and <italic>cox</italic>2) gene regions combined with extensive morphological and physiological properties of these isolates, including the ex‐type culture of <italic>P. cinnamomi</italic> var. <italic>parvispora</italic>, demonstrates that this taxon is unique and it is redesignated here as <italic>Phytophthora parvispora</italic> sp. nov. Although morphologically similar to <italic>P. cinnamomi</italic>, <italic> P. parvispora</italic> differs by its smaller‐sized sporangia, chlamydospores, oogonia and oospores, higher oospore wall index, single‐celled antheridia, higher minimum and maximum temperatures for growth and faster growth at optimum temperature. In the phylogeny, <italic>P. parvispora</italic> falls within <italic>Phytophthora </italic>ITS clade 7a, grouped in a well‐supported clade sister to <italic>P. cinnamomi</italic>. In pathogenicity tests, <italic>P. parvispora</italic> and <italic>P. cinnamomi</italic> were equally aggressive towards <italic>A. unedo</italic> seedlings. The possible geographic origin of <italic>P. parvispora</italic> is also discussed.</p> </abstract>