title: Evolutionary process of amino acid biosynthesis in Corynebacterium at the whole genome level.
abstract: Corynebacterium glutamicum, which is the closest relative of Corynebacterium efficiens, is widely used for the large scale production of many kinds of amino acids, particularly glutamic acid and lysine, by fermentation. Corynebacterium diphtheriae, which is well known as a human pathogen, is also closely related to these two species of Corynebacteria, but it lacks such productivity of amino acids. It is an important and interesting question to ask how those closely related bacterial species have undergone such significant functional differentiation in amino acid biosynthesis. The main purpose of the present study is to clarify the evolutionary process of functional differentiation among the three species of Corynebacteria by conducting a comparative analysis of genome sequences. When Mycobacterium and Streptomyces were used as out groups, our comparative study suggested that the common ancestor of Corynebacteria already possessed almost all of the gene sets necessary for amino acid production. However, C. diphtheriae was found to have lost the genes responsible for amino acid production. Moreover, we found that the common ancestor of C. efficiens and C. glutamicum have acquired some of genes responsible for amino acid production by horizontal gene transfer. Thus, we conclude that the evolutionary events of gene loss and horizontal gene transfer must have been responsible for functional differentiation in amino acid biosynthesis of the three species of Corynebacteria.
authors.affiliation: Institute of Life Sciences, Ajinomoto Co., Inc., Kawasaki, Japan.
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Nishio
authors.forename: Yoji
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Usuda
authors.forename: Shinichi
authors.initials: S
authors.lastname: Sugimoto
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Matsui
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kawarabayasi
authors.forename: Hisashi
authors.initials: H
authors.lastname: Kikuchi
authors.forename: Takashi
authors.initials: T
authors.lastname: Gojobori
authors.forename: Kazuho
authors.initials: K
authors.lastname: Ikeo
mesh_terms: D000596:Amino Acids / Q000096:biosynthesis*; D001482:Base Composition; D003352:Corynebacterium / Q000235:genetics* / Q000378:metabolism* / Q000472:pathogenicity; D003353:Corynebacterium diphtheriae / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity; D048230:Corynebacterium glutamicum / Q000235:genetics / Q000378:metabolism; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D019143:Evolution, Molecular; D017353:Gene Deletion; D022761:Gene Transfer, Horizontal; D005798:Genes, Bacterial; D016680:Genome, Bacterial; D006801:Humans; D008954:Models, Biological; D016366:Open Reading Frames; D010802:Phylogeny; D013045:Species Specificity
chemical_list: D000596:Amino Acids; D004269:DNA, Bacterial