Frequency and diversity of small cryptic plasmids in the genus Rahnella

BMC Microbiology

Research Article

Elena Petutschnig¹  David K Summers²  Brigitte Poppenberger³  Wilfried Rozhon³  Mamoona Khan³ 

[1] Albrecht-von-Haller-Institute of Plant Sciences, Georg-August-University Goettingen, Untere Karspuele 2, 37073, Goettingen, Germany;Department of Genetics, University of Cambridge, Downing Street, CB2 3EH, Cambridge, UK;Max F Perutz Laboratories, University of Vienna, Dr Bohrgasse 9, 1030, Vienna, Austria;

关键词: Lateral Gene Transfer;    Replication Origin;    Rolling Circle;    Translate Amino Acid Sequence;    Small Plasmid;   

DOI  :  10.1186/1471-2180-10-56

 received in 2009-07-17, accepted in 2010-02-19,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundRahnella is a widely distributed genus belonging to the Enterobacteriaceae and frequently present on vegetables. Although Rahnella has interesting agro-economical and industrial properties and several strains possess antibiotic resistances and toxin genes which might spread within microbial communities, little is known about plasmids of this genus. Thus, we isolated a number of Rahnella strains and investigated their complements of small plasmids.ResultsIn total 53 strains were investigated and 11 plasmids observed. Seven belonged to the ColE1 family; one was ColE2-like and three shared homology to rolling circle plasmids. One of them belonged to the pC194/pUB110 family and two showed similarity to poorly characterised plasmid groups. The G+C content of two rolling circle plasmids deviated considerably from that of Rahnella, indicating that their usual hosts might belong to other genera. Most ColE1-like plasmids formed a subgroup within the ColE1 family that seems to be fairly specific for Rahnella. Intriguingly, the multimer resolution sites of all ColE1-like plasmids had the same orientation with respect to the origin of replication. This arrangement might be necessary to prevent inappropriate synthesis of a small regulatory RNA that regulates cell division. Although the ColE1-like plasmids did not possess any mobilisation system, they shared large parts with high sequence identity in coding and non-coding regions. In addition, highly homologous regions of plasmids isolated from Rahnella and the chromosomes of Erwinia tasmaniensis and Photorhabdus luminescens could be identified.ConclusionsFor the genus Rahnella we observed plasmid-containing isolates at a frequency of 19%, which is in the average range for Enterobacteriaceae. These plasmids belonged to diffent groups with members of the ColE1-family most frequently found. Regions of striking sequence homology of plasmids and bacterial chromosomes highlight the importance of plasmids for lateral gene transfer (including chromosomal sequences) to distinct genera.

【 授权许可】

CC BY   
© Rozhon et al; licensee BioMed Central Ltd. 2010