Molecular Ecology and Evolution
Man in t Veld, Willem A. , van Brouwershaven, Ilse R. , Meijer, Harold J.G. .
Ancient clade splitting reveals enigmatic evolutionary history of Phytophthora citricola .
The population structure of Phytophthora citricola Sawada was examined by isozyme analysis (MDH, MDHP) and sequence analysis of the ITS regions and cox I . The strains were obtained by baiting in natural ecosystems in America, Europe and Turkey or isolated from diseased plants linked to the horticultural trade. Two Mdh-2 alleles and two Mdhp-1 alleles were observed, resulting in three electrophoretic types. Sequence analysis of the ITS regions resulted in thirteen haplotypes, grouping in two major and two minor clades. Sequence analysis of cox I revealed eleven haplotypes grouping in essentially similar clades. ET-1 and ET-2 have one Mdh-2 allele in common, suggesting geneflow between these clades. This was indeed confirmed by the presence of similar and nearly similar sequences in these ET's. ET-2 and ET-3 share one Mdhp-1 allele, suggesting also geneflow between these ET's. This was also confirmed by the presence of similar sequences in these ET's. In addition, as a whole the P. citricola clade was monophyletic in relation to the broad phylogeny of the genus Phytophthora. The newly described species P. multivora coincided with one of the major P. citricola clades. It is therefore doubtful whether this clade represents a distinct species, since, due to the observed gene flow, it is apparently not reproductively isolated from the other P. citricola clade. Moreover, this study demonstrated that the presence of P. multivora is not restricted to Western-Australia, but instead P. multivora was also present in natural ecosystems in Europe and Turkey and therefore does not represent a new biosecurity threat.
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1 - Plant Protection Service, Mycology, 15 Geertjesweg, P.O. Box 9102, Wageningen, Gelderland, 6700HC, The Netherlands
2 - Wageningen University , Laboratory of Phytopathology, 5 Binnenhaven, Wageningen, Gelderland, 6709NL, The Netherlands
Presentation Type: Poster:Posters for Topics
Location: Event Tent/Cliff Lodge
Date: Monday, July 27th, 2009
Time: 5:30 PM