Candidatus Carsonella ruddii

Taxobox
color = lightgrey
name = "Candidatus Carsonella ruddii"
regnum = Bacteria
phylum = Proteobacteria
classis = Gamma Proteobacteria
ordo = unclassified
genus = "Candidatus Carsonella"
species = "C. C. ruddii"
binomial = "Candidatus Carsonella ruddii"
binomial_authority =
synonyms = "Carsonella ruddii"

"Candidatus" Carsonella ruddii is an endosymbiotic Gamma Proteobacteria; it has the smallest genome of any characterised bacteria.cite journal | author = Nakabachi A, Yamashita A, Toh H, Ishikawa H, Dunbar H, Moran N, Hattori M | title = The 160-kilobase genome of the bacterial endosymbiont Carsonella. | journal = Science | volume = 314 | issue = 5797 | pages = 267 | year = 2006 | pmid = 17038615 | doi = 10.1126/science.1134196]

The species is an endosymbiont that is present in all species of phloem sap-feeding insects known as psyllids. [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] The endosymbionts occurs in a specialised structure known as the bacteriome.

In 2006 the genome of "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 species genome consists of a circular chromosome of 159,662 base pairs and that the genome has a high coding density (97%) with many overlapping genes and reduced gene length. The number of predicted genes was 182, also lowest in record. In comparison, "Mycoplasma genitalium", which has the smallest genome of any free-living organism, has a genome of 580,000 base pairs. Numerous genes considered essential for life seem to be missing, suggesting that the species may have achieved organelle-like status.

References

External links

* [http://www.kazusa.or.jp/codon/cgi-bin/showcodon.cgi?species=Candidatus+Carsonella+ruddii+%5Bgbbct%5D Candidatus Carsonella ruddii codon usage table]
* [http://www.sciam.com/article.cfm?chanID=sa003&articleID=00055E83-88E2-152E-88E283414B7F0000 Scientific American] – Tiny Genome May Reflect Organelle in the Making