An expanded phylogeny for the genus Phytophthora

Abstract

A comprehensive phylogeny representing 142 described and 43 provisionally named <i>Phytophthora</i> species is reported here for this rapidly expanding genus. This phylogeny features signature sequences of 114 ex-types and numerous authentic isolates that were designated as representative isolates by the originators of the respective species. Multiple new subclades were assigned in clades 2, 6, 7, and 9. A single species <i>P. lilii</i> was placed basal to clades 1 to 5, and 7. <i>Phytophthora stricta</i> was placed basal to other clade 8 species, <i>P. asparagi</i> to clade 6 and <i>P. intercalaris</i> to clade 10. On the basis of this phylogeny and ancestral state reconstructions, new hypotheses were proposed for the evolutionary history of sporangial papillation of <i>Phytophthora</i> species. Non-papillate ancestral <i>Phytophthora</i> species were inferred to evolve through separate evolutionary paths to either papillate or semi-papillate species.