Hexachlorocyclohexane-degrading bacterial strains Sphingomonas paucimobilis B90A, UT26 and Sp+, having similar lin genes, represent three distinct species, Sphingobium indicum sp. nov., Sphingobium japonicum sp. nov. and Sphingobium francense sp. nov., and reclassification of [Sphingomonas] chungbukensis as Sphingobium chungbukense comb. nov.
Three strains of Sphingomonas paucimobilis, B90A, UT26 and Sp+, isolated from different geographical locations, were found to degrade hexachlorocyclohexane. Phylogenetic analysis based on 16S rRNA gene sequences indicated that these strains do not fall in a clade that includes the type strain, Sphingomonas paucimobilis ATCC 29837(T), but form a coherent cluster with [Sphingomonas] chungbukensis IMSNU 11152(T) followed by Sphingobium chlorophenolicum ATCC 33790(T). The three strains showed low DNA-DNA relatedness values with Sphingomonas paucimobilis ATCC 29837(T) (8-25%), [Sphingomonas] chungbukensis IMSNU 11152(T) (10-17%), Sphingobium chlorophenolicum ATCC 33790(T) (23-54%) and Sphingomonas xenophaga DSM 6383(T) (10-28%), indicating that they do not belong to any of these species. Although the three strains were found to be closely related to each other based on 16S rRNA gene sequence similarity (99.1-99.4%), DNA-DNA relatedness (19-59%) and pulsed-field gel electrophoresis (PFGE) patterns indicated that they possibly represent three novel species of the genus Sphingobium. The three strains could also be readily distinguished by biochemical tests. The three strains showed similar polar lipid profiles and contained sphingoglycolipids. The strains differed from each other in fatty acid composition but contained the predominant fatty acids characteristic of other Sphingobium species. A phylogenetic study based on 16S rRNA gene sequences showed that [Sphingomonas] chungbukensis IMSNU 11152(T) formed a cluster with members of the genus Sphingobium. Based on these results, it is proposed that strains B90A, UT26 and Sp+, previously known as Sphingomonas paucimobilis, are the type strains of Sphingobium indicum sp. nov. (=MTCC 6364(T)=CCM 7286(T)), Sphingobium japonicum sp. nov. (=MTCC 6362(T)=CCM 7287(T)) and Sphingobium francense sp. nov. (=MTCC 6363(T)=CCM 7288(T)), respectively. It is also proposed that [Sphingomonas] chungbukensis be transferred to Sphingobium chungbukense comb. nov.
Pal
Rinku
R
Molecular Biology Laboratory, Department of Zoology, University of Delhi, Delhi - 110007, India.
Bala
Shashi
S
Molecular Biology Laboratory, Department of Zoology, University of Delhi, Delhi - 110007, India.
Dadhwal
Mandeep
M
Molecular Biology Laboratory, Department of Zoology, University of Delhi, Delhi - 110007, India.
Kumar
Mukesh
M
Molecular Biology Laboratory, Department of Zoology, University of Delhi, Delhi - 110007, India.
Dhingra
Gauri
G
Molecular Biology Laboratory, Department of Zoology, University of Delhi, Delhi - 110007, India.
Prakash
Om
O
Molecular Biology Laboratory, Department of Zoology, University of Delhi, Delhi - 110007, India.
Prabagaran
S R
SR
Center for Cellular and Molecular Biology, Hyderabad - 500007, India.
Shivaji
S
S
Center for Cellular and Molecular Biology, Hyderabad - 500007, India.
Cullum
John
J
Department of Genetics, University of Kaiserslautern, 67663 Kaiserslautern, Germany.
Holliger
Christof
C
EPFL, ENAC-ISTE, Laboratory of Environmental Biotechnology, CH 1015 Lausanne, Switzerland.
Lal
Rup
R
Molecular Biology Laboratory, Department of Zoology, University of Delhi, Delhi - 110007, India.
D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D015373:Bacterial Typing Techniques; D001673:Biodegradation, Environmental; D004269:DNA, Bacterial / Q000032:analysis; D004275:DNA, Ribosomal / Q000032:analysis; D020459:Genes, rRNA; D001556:Hexachlorocyclohexane / Q000378:metabolism*; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010641:Phenotype; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D042301:Sphingomonadaceae / Q000145:classification* / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D020578:Sphingomonas / Q000145:classification* / Q000201:enzymology / Q000235:genetics / Q000502:physiology
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D001556:Hexachlorocyclohexane