[From Pseudomonas taxonomy Genre: Retrospective and news]

Bacteria of the genus Pseudomonas belong to the family Pseudomonadaceae. They are ubiquitous and have a particular interest in medical, food, water and environmental microbiology and agronomy. Some species are potentially usable in the field of agriculture and for the sanitation of ecosystems polluted with xenobiotic compounds. The masterly work of Palleroni, based on ribosomal ribonucleic acid [rRNA] homology, has shown the depth heterogeneity in the genus Pseudomonas and resulted the reshuffle of this genus in 5 groups of rRNA homology. This restructuration was thereafter confirmed by recent investigations including numerical analysis of phenotypic characters, ubiquinone study, determination of the pattern of cellular fatty acids 3-hydroxy and 16S rRNA sequencing. Species taken as Pseudomonas [groups II to V of Palleroni] were assigned to preexisting genera or to new genera. Pseudomonas <> are authentic Pseudomonas and correspond to group 1 of Palleroni. The genus gathers about sixty species that are isolated from various ecosystems. These species may or may not produce fluorescent pigments called pyoverdines and can be distinguished from related genera by the presence of ubiquinone 9 and the specific cellular fatty acids 3-hydroxy [3-hydroxydecanoic [3-OH 10:0] and 3-hydroxydodecanoic [3-OH 12:0] acids] and are unable to accumulate the poly-beta-hydroxybutyrate