The topology of pufLM gene sequences inside of the OM60 NOR5 clade is approximately in accordance with all the phylogeny derived from 16S rRNA gene data, showing two primary branches comprising representatives from the NOR5 1 and NOR5 three lineages and also a third branch repre sented by Chromatocurvus halotolerans. Only the clus tering of H. rubra with Chromatocurvus halotolerans during the pufLM primarily based tree represents a discrepancy with the 16S rRNA phylogeny.
Having said that, no indications selleck chemicals of a hori zontal gene transfer of puf genes from distant phylogen etic lineages to members from the OM60 NOR5 clade were found, which can be in line with results obtained with repre sentatives with the purchase Chromatiales, a group of purple sulfur bacteria belonging towards the Gammaproteobacteria, This is in contrast for the Alphaproteobacteria and Betaproteobacteria, by which apparently horizontal gene transfer of pufL and pufM genes among phototrophic members has occurred, 1 doable explan ation for this divergence might be the variable genome structure in some members within the Alphaproteobacteria, primarily the Roseobacter clade, Nevertheless, a subsequent reduction of photosynthesis genes or horizontal transfer of photosynthesis genes inside of the OM60 NOR5 clade is still probable, thereby explaining the shut relation ship of phototrophic and non phototrophic species inside of this group. Nonetheless, our outcomes contradict a prior report postulating a polyphyletic origin of photosynthetic reaction center genes in members on the OM60 NOR5 clade primarily based on effects obtained with the strains HTCC2148 and HTCC2246, From the meanwhile, a draft genome sequence of HTCC2148 has become established, but pufLM gene fragments recognized by PCR in a prior report have been missing.
At this time, no genome sequence of strain HTCC2246 is obtainable, but it belongs like HTCC2148 to the NOR5 eight branch inside of the OM60 NOR5 clade, which doesn’t incorporate any known photograph trophic representatives to date, Additionally, we located in our evaluation a higher similarity on the pufLM genes ADL5859 of HTCC2246 using the Bradyrhizobium sp. strain S23321, Bradyrhizobium species are found within the rhizosphere of plants wherever they form root nodules. Hence, the pufLM genes of strain HTCC2246 should have been not too long ago transferred from a nitrogen repairing, soil bac terium forming root nodules. Nonetheless, this might be extremely unlikely, because strain HTCC2246 like most other acknowledged members in the OM60 NOR5 clade is actually a marine bacterium, which was isolated through the open sea water and never from soil. Consequently, we speculate that the re sults reported by Cho et al. could have been brought about by a contamination in the analyzed samples with cells or DNA of phototrophic alpha or betaproteobacteria inhabiting freshwater or soil, but not marine environments.