Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/25/2009
Publication Date: 8/25/2009
Citation: Labeda, D.P., Goodfellow, M. 2009. Reassessment of the Systematics of the Suborder Pseudonocardineae. Meeting Abstract. Interpretive Summary:
Technical Abstract: The suborder Pseudonocardineae proposed by Stackebrandt et al. in 1999 contained only a single family, Pseudonocardineae Embley et al. 1988. Labeda and Kroppenstedt  proposed, on the basis of phylogenetic analysis of a subset of all taxa within the family, that some of the genera be placed in the new family Actinosynnemataceae, which was supported in the recent study on the class Actinobacteria by Zhi et al. . The taxonomic status of the the families Actinosynnemataceae and Pseudonocardiaceae are assessed based on current 16S rRNA sequence, chemotaxonomic, and morphological, data and descriptions of the suborder Pseudonocardineae and its subordinate familes should be emended as warranted. 16S rRNA gene sequences for type strains of all taxa within the suborder Pseudonocardineae were obtained from the SILVA database or locally maintained alignments and subjected to phylogenetic analyses using ARBor phylogenetic software package (ARB) and Molecular Evolutionary Genetics Analysis software package (MEGA). Morphological and chemotaxonomic charactertistics for the genera were compiled from the literature and evolution of these traits within the suborder were evaluated using the MESQUITE software package. Phylogenetic analyses of 16S rRNA gene sequence data for all taxa within the suborder do not support the current description of the Actinosynnemataceae. The phylogenetic analyses and chemotaxonomic data do support emending the description of the family Actinosynnemataceae to include only the genera Actinosynnema, Lechevalieria, Lentzea, Saccharothrix, and Umezawaea. The phylogenetic analyses suggest that the suborder Pseudonocardineae could contain several families, but this is not statistically well supported nor consistent with the observed chemotaxonomic characteristics of the genera. The family divisions within the suborder Pseudonocardineae as presently defined are no longer correct. The suborder Pseudonocardineae likely contains more than one family, but the phylogenetic and phenotypic data available at this time are inadequate to clearly delineate the appropriate groupings of genera.