Planctomycetes review

Fuerst and Sagulenko (Nature Review Microbiology 2011) present a nice review of the current knowledge of the Planctomycetes. They focus particularly on the genus Gemmata because of its endomembrane system seemingly surrounding the DNA, the presence of eukaryotic-like membrane coat proteins in its proteome and its capacity to do endocytosis. They conclude that:

"The compartmentalization of planctomycetes challenges our hypotheses regarding the origins of eukaryotic organelles."

This article nicely highlight the importance of studying other non-classical model of bacterial cell biology, like E. coli. There is also lots of phylogenetic interesting facts, evolution stimulating hints and questions are spread throughout the article.
They conclude with some hypothesis concerning the possible link between those bacteria and the origin of the eukaryotes, including convergent evolution, bacteria invention followed by LGT to the ancestral eukaryote, or LGT from the eukaryotes to the Planctomycetes and a complex LUCA. However, may be the strongest deduction is the following:

"Nevertheless, it seems clear that the planctomycetes are now a strong challenge to the idea that some form of fusion between archaeal and bacterial cells was necessary to evolve the eukaryote and its nucleus."

Whatever the correct answer, it is clear that Planctomycetes are fascinating bacteria that will keep us busy for the next couple of years. Keep watching!