Diversification of Pseudomonas corrugata 2140 produces new phenotypes altered in GC-FAME, BIOLOG, and in vitro inhibition profiles and taxonomic identification

Bacteria are known to rapidly produce new phenotypes, but it is unclear how phenotype "plasticity" relates to studies on the population ecology of bac teria in complex environments. We characterised a collection of 14 spontane ous phenotype variants, derived from in vitro and in vivo cultures (wheat r oots) of Pseudomonas corrugata 2140, using fatty acid methyl ester profiles (GC-FAME), carbon substrate utilisation (BIOLOG), and in vitro inhibition against seven soil microorganisms. All three phenotype profiles indicated m arked differences between some variants and the parent isolate. Some varian t types were classified taxonomically by GC-FAME as different species to th eir wild-type parent, and up to a Euclidian distance of 11 from their paren t. Taxonomic identification by the BIOLOG assay was more consistent; howeve r, use of 22 carbon sources were altered (lost or gained) in one or more va riants. All variant types had a reduced ability to inhibit one or more test organisms, depending on the variant and test organism. Hierarchical cluste r analysis of variants using GC-FAME, BIOLOG, and inhibition profiles produ ced different groupings. The ability of variants to cross taxonomic boundar ies specified by the GC-FAME and BIOLOG libraries at the species level has implications for both taxonomy and the ecological study of bacterial commun ities.