Grouping of Plant-Pathogenic and Some Other Pseudomonas spp. by Using Cellular Fatty Acid Profiles

Abstract

Approximately 500 fatty acid profiles were prepared for 340 strains of plant-pathogenic and other bacteria currently or recently classified in the genus Pseudomonas Migula 1984. Strains representing some infraspecific taxa were included. The fatty acid profiles were stable and reproducible provided that cultural and chemical techniques were standardized. The 2- and 3-hydroxy fatty acids were found to be useful in grouping strains into six major groups, several of which were further differentiated into subgroups. Group 1 contained strains of the following species and subspecies: Pseudomonas aeruginosa, P. agarici, P. asplenii, P. aureofaciens, P. caricapapayae, P. chlororaphis, P. cichorii, P. ficuserectae, P. fluorescens, P. fuscovaginae, “P. gingeri,” P. marginalis, P. meliae, P. putida, “P. reactans,” P. syringae, P. tolaasii, and P. viridiflava (subgroup 1a); P. corrugata (subgroup 1b); P. rubrisubalbicans (subgroup 1c); P. alcaligenes, P. pseudoalcaligenes subsp. Pseudoalcaligenes, and P. stutzeri (subgroup 1d); P. amygdali (subgroup le); and P. cattleyae NCPPB 1874 (subgroup 1f). All group 1 strains contained 10:0 3-OH and 12:0 3-OH, and most group 1 strains also contained 12:0 2-OH. Group 2 contained strains belonging to the following taxa: P. andropogonis, P. caryophylli, P. cepacia, P. gladioli, P. plantarii, and P. glumae (in part) (subgroup 2a); P. glumae (in part) (subgroup 2b); and P. solanacearum, P. syzygii, and the banana blood disease bacterium (subgroup 2c). All of the group 2 strains contained 14:0 3-OH, 16:0 3-OH, and 18:1 2-OH; most also contained 16:1 2-OH and 16:0 2-OH. Group 3 contained strains belonging to the following taxa: Comamonas acidovorans, P. avenae, P. cattleyae NCPPB 961, P. pseudoalcaligenes subsp. citrulli, P. pseudoalcaligenes subsp. konjaci, P. rubrilineans (subgroup 3a); and Comamonas testosteroni (subgroup 3b). All of the group 3 strains contained 10:0 3-OH. The group 4 strains were members of Sphingomonas paucimobilis, and all contained only 14:0 2-OH. The group 5 strains were members of P. ftectens and contained 12:0 2-OH, 14:0 2-OH, and 14:0 3-OH. The group 6 strains were P. betle, P. cissicola, P. hibiscicola, Xanthomonas maltophilia, and Xanthomonas campestris pv. campestris strains, and all contained 12:0 3-OH, 11:0 iso 3-OH, and 13:0 iso 3-OH. Within each group or subgroup, qualitative and quantitative differences in profiles occurred for most species. Differences were also found at the infraspecific level for some taxa. My results support genomic and other data which show that the plant-pathogenic and other pseudomonads tested should be placed in at least six genera.