Stenotrophomonas maltophilia genomes: A start-up comparison

The whole DNA sequences of 2 Stenotrophomonas maltophilia strains isolated from the blood of a cancer patient (K279a) and the poplar Populus trichocarpa (R551-3) have been compared. The 2 chromosomes exhibit extensive synteny, but each is punctuated by about 40 genomic islands (GEIs), which vary in size from 3 to 70 kb, and may encode up to about 50 proteins. A large set of smaller DNA sequences, encoding strain-specific 'solo' orfs, contributes to genetic heterogeneity in a significant manner. S. maltophilia GEIs potentially encode several proteins mediating interactions with the environment such as transmembrane proteins, haemagglutinins, components of type I and IV secretion systems, and efflux proteins having a role in metal and/or drug resistance. The presence of specific GEIs in the S. maltophilia population was monitored by PCR and slot-blot analyses. Data suggest that some islands are present at sites different from those identified in K279a and that alternative islands may be integrated at mapped sites. (C) 2009 Elsevier GmbH. All rights reserved.