Title: Systematics of Plant-Pathogenic and Related Streptomyces Species Based on Phylogenetic Analyses of Multiple Gene Loci Author
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 27, 2010
Publication Date: March 27, 2010
Citation: Labeda, D.P. 2010. Systematics of Plant-Pathogenic and Related Streptomyces Species Based on Phylogenetic Analyses of Multiple Gene Loci. Meeting Abstract. Technical Abstract: The 10 species of Streptomyces implicated as the etiological agents in scab disease of potatoes or soft rot disease of sweet potatoes are distributed among 7 different phylogenetic clades in analyses based on 16S rRNA gene sequences, but high sequence similarity of this gene among Streptomyces species provides limited taxonomic resolution at the species level. Sequencing and phylogenetic analyses of the house-keeping gene loci atpD, recA, rpoB, and trpB was evaluated for improved resolution of the relationships between phytopathogenic species and other closely related species. Phylogenetic relationships observed for individual house-keeping genes in this study did not always agree with those inferred from analysis of 16S rRNA gene sequences alone. In analyses of a concatenated sequence alignment for the 4 house-keeping genes (2111 bp), as well as a 5 gene alignment that included the 16S rRNA gene sequence (3401 bp), the plant pathogenic species were distributed into 5 distinct clades. S. bottropensis, S. europaeiscabiei, S. scabiei, and S. stelliscabiei formed a statistically well-supported clade in 3 of the 4 house-keeping gene phylogenetic trees, as well as those constructed using both the 4 and 5 gene concatenated aligments. S. turgidiscabies and S. reticuliscabiei have been reported to represent a single genomic species, but the type strains could be differentiated based on differences in sequences of the atpD and trpB genes.. Analyses based on concatenated alignments of sequences of 4 house-keeping genes, with and without the inclusion of 16S rRNA genes sequences, provided a better estimation of species relationships within this genus than the 16S rRNA gene phylogeny alone. A proposal to reduce a number of species included in this study to synonym can be supported on the basis of the multi-gene phylogeny presented.