title: The diverse bacterial origins of the Arabidopsis polyamine biosynthetic pathway.
abstract: We functionally identified the last remaining step in the plant polyamine biosynthetic pathway by expressing an Arabidopsis thaliana agmatine iminohydrolase cDNA in yeast. Inspection of the whole pathway suggests that the arginine decarboxylase, agmatine iminohydrolase, N-carbamoylputrescine amidohydrolase route to putrescine in plants was inherited from the cyanobacterial ancestor of the chloroplast. However, the rest of the pathway including ornithine decarboxylase and spermidine synthase was probably inherited from bacterial genes present in the original host cell, common ancestor of plants and animals, that acquired the cyanobacterial endosymbiont. An exception is S-adenosylmethionine decarboxylase, which may represent a eukaryote-specific enzyme form.
authors.affiliation: Division of Food Safety Science, Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, UK.
authors.forename: Crista
authors.initials: C
authors.lastname: Illingworth
authors.forename: Melinda J
authors.initials: MJ
authors.lastname: Mayer
authors.forename: Katherine
authors.initials: K
authors.lastname: Elliott
authors.forename: Colin
authors.initials: C
authors.lastname: Hanfrey
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Walton
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Michael
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D002736:Chloroplasts; D003001:Cloning, Molecular; D000458:Cyanobacteria / Q000201:enzymology* / Q000235:genetics; D019143:Evolution, Molecular; D020224:Expressed Sequence Tags; D017343:Genes, Plant; D006867:Hydrolases / Q000235:genetics*; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics; D011073:Polyamines; D011700:Putrescine / Q000096:biosynthesis*; D016415:Sequence Alignment
chemical_list: D010940:Plant Proteins; D011073:Polyamines; D006867:Hydrolases; C019626:agmatine deiminase; D011700:Putrescine