title: Nature lessons: The whitefly bacterial endosymbiont is a minimal amino acid factory with unusual energetics.
abstract: Reductive genome evolution is a universal phenomenon observed in endosymbiotic bacteria in insects. As the genome reduces its size and irreversibly losses coding genes, the functionalities of the cell system, including the energetics processes, are more restricted. Several energetic pathways can also be lost. How do these reduced metabolic networks sustain the energy needs of the system? Among the bacteria with reduced genomes Candidatus Portiera aleyrodidarum, obligate endosymbiont of whiteflies, represents an extreme case since lacks several key mechanisms for ATP generation. Thus, to analyze the cell energetics in this system, a genome-scale metabolic model of this endosymbiont was constructed, and its energy production capabilities dissected using stoichiometric analysis. Our results suggest that energy generation is coupled to the synthesis of essential amino acids and carotenoids, crucial metabolites in the symbiotic association. A deeper insight showed that ATP production via carotenoid synthesis is also connected with amino acid production. This unusual association of energy production with anabolism suggests that, although minimized, endosymbiont metabolic networks maintain a remarkable biosynthetic potential.
authors.affiliation: Departamento de Bioquímica y Biología Molecular I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria, Madrid 28045, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Calle-Espinosa
authors.affiliation: Departamento de Bioquímica y Biología Molecular I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria, Madrid 28045, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Ponce-de-Leon
authors.affiliation: Department of Entomology, The Hebrew University of Jerusalem, Israel.
authors.forename: Diego
authors.initials: D
authors.lastname: Santos-Garcia
authors.affiliation: Institute for Integrative Systems Biology (I2SysBio), Universitat de València-CSIC, C/José Beltrán 2, Paterna 46980, Spain; Departament de Genètica, Universitat de València, Spain.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Silva
authors.affiliation: Departamento de Bioquímica y Biología Molecular I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria, Madrid 28045, Spain. Electronic address: framonte@quim.ucm.es.
authors.forename: Francisco
authors.initials: F
authors.lastname: Montero
authors.affiliation: Institute for Integrative Systems Biology (I2SysBio), Universitat de València-CSIC, C/José Beltrán 2, Paterna 46980, Spain; Departament de Bioquímica i Biologia Molecular, Universitat de València, Spain. Electronic address: Juli.Pereto@uv.es.
authors.forename: Juli
authors.initials: J
authors.lastname: Peretó
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D004734:Energy Metabolism; D016680:Genome, Bacterial; D044129:Halomonadaceae / Q000235:genetics / Q000378:metabolism*; D006430:Hemiptera / Q000382:microbiology*; D064688:Metabolic Flux Analysis; D053858:Metabolic Networks and Pathways; D008954:Models, Biological; D013559:Symbiosis; D019207:beta Carotene / Q000378:metabolism
chemical_list: D000596:Amino Acids; D019207:beta Carotene
keywords: Carotenoids; Elementary flux modes; Essential amino acids; Portiera aleyrodidarum