Contributors: Virginia Commonwealth University (VCU); Department of Parasitology São Paulo (IBS); Institute of Biomedical Sciences (ICB/USP); Universidade de São Paulo = University of São Paulo (USP)-Universidade de São Paulo = University of São Paulo (USP); Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE); Université Claude Bernard Lyon 1 (UCBL); Université de Lyon-Université de Lyon-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS); Laboratorio Nacional de Computação Cientifica Rio de Janeiro (LNCC / MCT); An algorithmic view on genomes, cells, and environments (BAMBOO); Centre Inria de l'Université Grenoble Alpes; Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE); Université de Lyon-Université de Lyon-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL); Baobab LBBE; Département PEGASE LBBE (PEGASE); Université de Lyon-Université de Lyon-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE); Laboratório de Ultraestrutura Celular Hertha Meyer - IBCCF / UFRJ Rio de Janeiro; Instituto de Biofísica Carlos Chagas Filho Rio de Janeiro (IBCCF / UFRJ); Universidade Federal do Rio de Janeiro Brasil = Federal University of Rio de Janeiro Brazil = Université fédérale de Rio de Janeiro Brésil (UFRJ)-Universidade Federal do Rio de Janeiro Brasil = Federal University of Rio de Janeiro Brazil = Université fédérale de Rio de Janeiro Brésil (UFRJ); ANR-08-BLAN-0293,MIRI,Combinatorial exploration of the molecular landscape and evolution of intimate species relations(2008); European Project: 247073,ERC-2009-AdG,ERC-2009-AdG,SISYPHE(2010)
نبذة مختصرة : International audience ; Background Trypanosomatids of the genera Angomonas and Strigomonas live in a mutualistic association characterized by extensive metabolic cooperation with obligate endosymbiotic Betaproteobacteria. However, the role played by the symbiont has been more guessed by indirect means than evidenced. Symbiont-harboring trypanosomatids, in contrast to their counterparts lacking symbionts, exhibit lower nutritional requirements and are autotrophic for essential amino acids. To evidence the symbiont's contributions to this autotrophy, entire genomes of symbionts and trypanosomatids with and without symbionts were sequenced here. Results Analyses of the essential amino acid pathways revealed that most biosynthetic routes are in the symbiont genome. By contrast, the host trypanosomatid genome contains fewer genes, about half of which originated from different bacterial groups, perhaps only one of which (ornithine cyclodeaminase, EC:4.3.1.12) derived from the symbiont. Nutritional, enzymatic, and genomic data were jointly analyzed to construct an integrated view of essential amino acid metabolism in symbiont-harboring trypanosomatids. This comprehensive analysis showed perfect concordance among all these data, and revealed that the symbiont contains genes for enzymes that complete essential biosynthetic routes for the host amino acid production, thus explaining the low requirement for these elements in symbiont-harboring trypanosomatids. Phylogenetic analyses show that the cooperation between symbionts and their hosts is complemented by multiple horizontal gene transfers, from bacterial lineages to trypanosomatids, that occurred several times in the course of their evolution. Transfers occur preferentially in parts of the pathways that are missing from other eukaryotes. Conclusion We have herein uncovered the genetic and evolutionary bases of essential amino acid biosynthesis in several trypanosomatids with and without endosymbionts, explaining and complementing decades of experimental results. We ...
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