Partial rDNA sequences were obtained from 26 isolates representing species of Cercospora, Passalora, Paracercospora, Pseudocercospora, Ramulispora, Pseudocercosporella and Mycocentrospora. The combined internal transcribed spacers (ITS) including the 5.8S rRNA gene and 5' end of the 25S gene (primer pairs F63/R635) on rDNA were amplified using PCR and sequenced directly. The ITS regions including the 5.8S varied in length from 502 to 595 bp. The F63/R635 region varied from 508 to 519 bp among isolates sequenced. Reconstructed phylogenies inferred from both regions had highly similar topologies for the taxa examined. Phylogenetic analysis of the sequences resulted in four well-supported clades corresponding to Cercospora, Paracercospora/Pseudocercospora, Passalora and Ramulispora, with bootstrap values greater than 92% for each clade. Based on the results of the analysis, a new combination for Pseudocercosporella aestiva is proposed in Ramulispora, and Paracercospora is reduced to synonymy with Pseudocercospora.
Bibliographical noteFunding Information:
This research was supported in part by the Lieberman-Okinow Chair for Disease Resistance Breeding in Cereal Crops, Department of Plant Pathology, University of Minnesota to the senior author. Support for this research was also provided by the College of Agricultural Sciences, The Pennsylvania State University, University Park, PA. Mention of a trademark or proprietary product does not constitute a guarantee or warranty by the U.S. Department of Agriculture nor imply its approval to the exclusion of other products that may also be suitable. The authors are pleased to acknowledge Dr David Geiser for his pre-review comments on the manuscript. Aligned sequences are deposited in TreeBase, Harvard University.