title: Phylogenetic relationships among plant and animal parasites, and saprotrophs in Aphanomyces (Oomycetes).
abstract: Molecular phylogenetic relationships among 12 species of Aphanomyces de Bary (Oomycetes) were analyzed based on 108 ITS sequences of nuclear rDNA. Sequences used in the analyses belonged to the major species currently available in pure culture and GenBank. Bayesian, maximum likelihood, and maximum parsimony analyses support that Aphanomyces constitutes a monophyletic group. Three independent lineages were found: (i) plant parasitic, (ii) animal parasitic, and (iii) saprotrophic or opportunistic parasitic. Sexual reproduction appeared to be critical in plant parasites for survival in soil environments while asexual reproduction seemed to be advantageous for exploiting specialization in animal parasitism. Repeated zoospore emergence seems to be an advantageous property for both plant and animal parasitic modes of life. Growth in unspecific media was generally faster in saprotrophs compared with parasitic species. A number of strains and GenBank sequences were found to be misidentified. It was confirmed molecularly that Aphanomyces piscicida and Aphanomyces invadans appear to be conspecific, and found that Aphanomyces iridis and Aphanomyces euteiches are closely related, if not the same, species. This study has shown a clear evolutionary separation between Aphanomyces species that are plant parasites and those that parasitize animals. Saprotrophic or opportunistic species formed a separate evolutionary lineage except Aphanomyces stellatus whose evolutionary position has not yet been resolved.
authors.affiliation: Real Jardín Botánico CSIC, Madrid, Spain. dieguez@rjb.csic.es
authors.forename: Javier
authors.initials: J
authors.lastname: Diéguez-Uribeondo
authors.forename: Miguel A
authors.initials: MA
authors.lastname: García
authors.forename: Lage
authors.initials: L
authors.lastname: Cerenius
authors.forename: Eva
authors.initials: E
authors.lastname: Kozubíková
authors.forename: Isabel
authors.initials: I
authors.lastname: Ballesteros
authors.forename: Carol
authors.initials: C
authors.lastname: Windels
authors.forename: John
authors.initials: J
authors.lastname: Weiland
authors.forename: Howard
authors.initials: H
authors.lastname: Kator
authors.forename: Kenneth
authors.initials: K
authors.lastname: Söderhäll
authors.forename: María P
authors.initials: MP
authors.lastname: Martín
mesh_terms: D000818:Animals; D044744:Aphanomyces / Q000145:classification* / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D016000:Cluster Analysis; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D010273:Parasitic Diseases, Animal / Q000382:microbiology; D010802:Phylogeny; D010944:Plants / Q000469:parasitology; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D013172:Spores, Fungal / Q000254:growth & development
chemical_list: D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer