A Proposal To Reclassify Nocardia pinensis Blackall et al. as Skermania piniformis gen. nov., comb. nov.

Researchers reclassified Nocardia pinensis, an actinomycete originally isolated from activated-sludge sewage treatment plants, based on molecular and chemotaxonomic evidence. Using 16S rRNA gene sequencing, the authors determined that N. pinensis forms a distinct phylogenetic lineage most closely related to the genus Gordona, separate from true Nocardia species. Phylogenetic analysis using four different tree-building algorithms (Fitch-Margoliash, maximum-likelihood, maximum-parsimony, and neighbor-joining) consistently showed N. pinensis as a sister taxon to Gordona with 84% bootstrap support. Chemotaxonomic analysis revealed unique characteristics including hexahydrogenated menaquinones with eight isoprene units (with two cyclized end units), mycolic acids of 58-64 carbons, and specific phospholipid and fatty acid profiles. These combined genomic, chemotaxonomic, and phenotypic data supported creating a new genus. The authors propose reclassifying N. pinensis as Skermania piniformis gen. nov., comb. nov., and provide detailed descriptions of both the new genus and species, including morphological characteristics, growth conditions, and enzymatic substrate utilization patterns.

Key findings

• 16S rRNA sequencing revealed N. pinensis forms a distinct phylogenetic lineage most closely associated with Gordona rather than Nocardia species
• Unique chemotaxonomic features include hexahydrogenated menaquinones with eight isoprene units and cyclized end units (previously thought unique to Nocardia), plus mycolic acids of 58-64 carbons
• Phenotypic properties distinguish the organism from all seven previously described mycolic acid-containing genera
• Phylogenetic analysis using four independent tree-building methods consistently supported the new genus classification
• N. pinensis is proposed to be reclassified as Skermania piniformis, a new genus within the family Nocardiaceae