01905nas a2200253 4500008004100000022001400041245006400055210006200119300001000181490000700191520118100198653001401379653003301393653000801426653001701434653001201451653000901463100001701472700001401489700001601503700001401519700001701533856010101550 2000 eng d a1087-184500aA molecular phylogeny of Phytophthora and related Oomycetes0 amolecular phylogeny of Phytophthora and related Oomycetes a17-320 v303 a

Phylogenetic relationships among 50 Phytophthora species and between Phytophthora and other oomycetes were examined on the basis of the ITS sequences of genomic rDNA. Phytophthora grouped with Pythium, Peronospora, and Halophytophthora, distant from genera in the Saprolegniales. Albugo was intermediate between these two groups. Unlike Pythium, Phytophthora was essentially monophyletic, all but three species forming a cluster of eight clades. Two clades contained only species with nonpapillate sporangia. The other six clades included either papillate and semipapillate, or semipapillate and nonpapillate types, transcending traditional morphological groupings, which are evidently not natural assemblages. Peronospora was related to P. megakarya and P. palmivora and appears to be derived from a Phytophthora that has both lost the ability to produce zoospores and become an obligate biotroph. Three other Phytophthoras located some distance from the main Phytophthora-Peronospora cluster probably represent one or more additional genera.

10aevolution10ainternal transcribed spacers10aITS10aPeronospora.10aPythium10arDNA1 aCooke, D E L1 aDrenth, A1 aDuncan, J M1 aWagels, G1 aBrasier, C M uhttp://www.sciencedirect.com/science/article/B6WFV-45FC03G-1G/2/1cb8ec25d08dae3a16f56e74cd92e99e