Biosynthesis of Vitamins and Cofactors in Bacterium-Harbouring Trypanosomatids Depends on the Symbiotic Association as Revealed by Genomic Analyses

摘要: Some non-pathogenic trypanosomatids maintain a mutualistic relationship with betaproteobacterium of the Alcaligenaceae family. Intensive nutritional exchanges have been reported between two partners, indicating that these protozoa are excellent biological models to study metabolic co-evolution. We previously sequenced and herein investigate entire genomes five which harbor symbiotic bacterium (SHTs for Symbiont-Haboring Trypanosomatids) respective bacteria (TPEs Trypanosomatid Proteobacterial Endosymbiont), as well without symbionts (RTs Regular Trypanosomatids), presence genes classical pathways vitamin biosynthesis. Our data show biosynthetic thiamine, biotin, nicotinic acid absent from all trypanosomatid genomes. This is in agreement absolute growth requirement vitamins Also RTs synthesis pantothenic acid, folic riboflavin, B6. also available showing auxotrophic essential vitamins. On other hand, SHTs autotrophic such Indeed, corresponding were identified, most them symbiont genomes, while few genes, mostly eukaryotic origin, found host The only exceptions latter are: gene coding enzyme ketopantoate reductase (EC:1.1.1.169) related instead Firmicutes bacteria; one involved salvage pathway ubiquinone, Gammaproteobacteria. Their may result lateral transfer. Taken together, our results reinforce idea low associated bacterium, contains production.