title: Deficiency of a plastidial adenylate kinase in Arabidopsis results in elevated photosynthetic amino acid biosynthesis and enhanced growth.
abstract: An Arabidopsis (Arabidopsis thaliana) L. Heynh mutant deficient in an isoform of adenylate kinase (ADK; At2g37250) was isolated by reverse genetics. It contains a T-DNA insertion 377 bp downstream of the start point of transcription. The mutant lacks At2g37250 transcripts and has a mild reduction in total cellular ADK activity. Green fluorescent protein-fusion based cellular localization experiments, carried out with the full-length At2g37250, suggested a plastidial localization for this isoform. In keeping with this observation, organelle isolation experiments revealed that the loss in ADK activity was confined to the inner plastid. This plastid stroma ADK gene was found to be expressed tissue constitutively but at much higher levels in illuminated leaves. Phenotypic and biochemical analyses of the mutant revealed that it exhibited higher amino acid biosynthetic activity in the light and was characterized by an enhanced root growth. When the mutant was subjected to either continuous light or continuous dark, growth phenotypes were also observed in the shoots. While the levels of adenylates were not much altered in the leaves, the pattern of change observed in the roots was consistent with the inhibition of an ATP-consuming reaction. Taken together, these data suggest a role for the plastid stromal ADK in the coordination of metabolism and growth, but imply that the exact importance of this isoform is tissue dependent.
authors.affiliation: Department Willmitzer, Max-Planck-Institut für Molekulare Pflanzenphysiologie, 14476 Golm, Germany.
authors.forename: Fernando
authors.initials: F
authors.lastname: Carrari
authors.forename: Danahe
authors.initials: D
authors.lastname: Coll-Garcia
authors.forename: Nicolas
authors.initials: N
authors.lastname: Schauer
authors.forename: Anna
authors.initials: A
authors.lastname: Lytovchenko
authors.forename: Natalia
authors.initials: N
authors.lastname: Palacios-Rojas
authors.forename: Ilse
authors.initials: I
authors.lastname: Balbo
authors.forename: Mario
authors.initials: M
authors.lastname: Rosso
authors.forename: Alisdair R
authors.initials: AR
authors.lastname: Fernie
mesh_terms: D000263:Adenylate Kinase / Q000235:genetics / Q000378:metabolism*; D000596:Amino Acids / Q000096:biosynthesis*; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D050260:Carbohydrate Metabolism; D002940:Circadian Rhythm; D004269:DNA, Bacterial; D018506:Gene Expression Regulation, Plant; D005810:Multigene Family; D009154:Mutation; D010788:Photosynthesis / Q000502:physiology*; D018515:Plant Leaves / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D018087:Plastids / Q000201:enzymology*; D012639:Seeds / Q000378:metabolism
chemical_list: D000596:Amino Acids; D004269:DNA, Bacterial; C036483:T-DNA; D000263:Adenylate Kinase