Candidatus Carsonella ruddii
|Candidatus Carsonella ruddii|
|Species:||Ca. C. ruddii|
|Candidatus Carsonella ruddii
Thao et al. 2000
Candidatus Carsonella ruddii is an obligate endosymbiotic Gamma Proteobacterium; it has one of the smallest genomes of any characterised bacteria. Nasuia deltocephalinicola is now considered to have the known smallest genome in bacteria (112kb).
In 2006 the genome of Ca. C. ruddii strain Pv (Carsonella-Pv) of the hackberry petiole gall psyllid, Pachypsylla venusta, was sequenced at RIKEN in Japan and the University of Arizona. It was shown that the genome consists of a circular chromosome of 159,662 base pairs and that it has a high coding density (97%) with many overlapping genes and reduced gene length. The number of predicted genes was 182, also the lowest on record (NCBI-Genome). In comparison, Mycoplasma genitalium, which has the smallest genome of any free-living organism, has a genome of 521 genes. Numerous genes considered essential for life seem to be missing, suggesting that the species may have achieved organelle-like status.
- Spaulding, A. W. and C. D. von Dohlen. 1998. Phylogenetic Characterization and Molecular Evolution of Bacterial Endosymbionts in Psyllids (Hemiptera: Sternorrhyncha). Molecular Biology and Evolution 15(11):1506-1513
- Nakabachi A, Yamashita A, Toh H, Ishikawa H, Dunbar H, Moran N, Hattori M (2006). "The 160-kilobase genome of the bacterial endosymbiont Carsonella.". Science 314 (5797): 267. doi:10.1126/science.1134196. PMID 17038615.
- Thao, M.L. 2000. Cospeciation of Psyllids and Their Primary Prokaryotic Endosymbionts. Applied and Environmental Microbiology 66:2898-2905
- Thao, M.L. 2001. Phylogenetic analysis of vertically transmitted psyllid endosymbionts (Candidatus Carsonella ruddii) based on atpAGD and rpoC: comparisons with 16S-23S rDNA-derived phylogeny. Current Microbiology 42:419-21 PMID 11381334
- Scientific American – Tiny Genome May Reflect Organelle in the Making