This Article Full Text Full Text (PDF) Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Villa, N. O. Articles by Suga, H. Search for Related Content PubMed Articles by Villa, N. O. Articles by Suga, H. Agricola Articles by Villa, N. O. Articles by Suga, H.

Phylogenetic relationships of Pythium and Phytophthora species based on ITS rDNA, cytochrome oxidase II and ß-tubulin gene sequences

     Genetics and Molecular Biology Division, Institute of Biological Sciences, University of the Philippines Los Baños, College, Laguna, Philippines 4031

Koji Kageyama ¹
Takahiro Asano

     River Basin Research Center, Gifu University, 1-1 Yanagido, Japan 501-1193

Haruhisa Suga

     Life Science Research Center, Gifu University, 1-1 Yanagido, Japan 501-1193

Fifty-eight isolates representing 39 Pythium species and 17 isolates representing nine Phytophthora species were chosen to investigate intra- and intergeneric relationships with sequence analysis of three genomic areas. The internal transcribed spacer regions (ITS1 and ITS2), including the 5.8S gene of the ribosomal DNA were PCR amplified with the universal primers ITS1 and ITS4. On the other hand 563 bp of the cytochrome oxidase II (cox II) gene was amplified with the primer pair FM66 and FM58 for Pythium and FM75 and FM78 for Phytophthora. The 658 bp partial ß-tubulin gene was amplified with the forward primer BT5 and reverse primer BT6. Maximum parsimony analysis of the three DNA regions revealed four major clades, reflective of sporangial morphology. Clade 1 was composed of Pythium isolates that bear filamentous to lobulate sporangia. Clade 2 represents Pythium isolates that bear globose to spherical zoosporangia or spherical hyphal swellings. Meanwhile Phytophthora isolates were lumped into Clade 3 wherein the papillate, semipapillate and nonpapillate species occupied separate subclades. Lastly, Clade 4 was composed of Pythium species that bear subglobose sporangia resembling the papillate sporangia observed in Phytophthora. Hence a number of species (Ph. undulata, P. helicoides, P. ostracodes, P. oedochilum and P. vexans) have been proposed to be the elusive intermediate species in the Pythium-to-Phytophthora evolutionary line.

Key words: molecular phylogeny, oomycetes, Pythiales

This article has been cited by other articles:

				E. Moralejo, A. Clemente, E. Descals, L. Belbahri, G. Calmin, F. Lefort, C. F.J. Spies, and A. McLeod Pythium recalcitrans sp. nov. revealed by multigene phylogenetic analysis. Mycologia, March 1, 2008; 100(2): 310 - 319. [Abstract] [Full Text] [PDF]