title: Lysine metabolism in antisense C-hordein barley grains.
abstract: The grain proteins of barley are deficient in lysine and threonine due to their low concentrations in the major storage protein class, the hordeins, especially in the C-hordein subgroup. Previously produced antisense C-hordein transgenic barley lines have an improved amino acid composition, with increased lysine, methionine and threonine contents. The objective of the study was to investigate the possible changes in the regulation of key enzymes of the aspartate metabolic pathway and the contents of aspartate-derived amino acids in the nontransgenic line (Hordeum vulgare L. cv. Golden Promise) and five antisense C-hordein transgenic barley lines. Considering the amounts of soluble and protein-bound aspartate-derived amino acids together with the analysis of key enzymes of aspartate metabolic pathway, we suggest that the C-hordein suppression did not only alter the metabolism of at least one aspartate-derived amino acid (threonine), but major changes were also detected in the metabolism of lysine and methionine. Modifications in the activities and regulation of aspartate kinase, dihydrodipicolinate synthase and homoserine dehydrogenase were observed in most transgenic lines. Furthermore the activities of lysine α-ketoglutarate reductase and saccharopine dehydrogenase were also altered, although the extent varied among the transgenic lines.
authors.affiliation: Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba CEP 13418-900, Brazil.
authors.forename: Daiana
authors.initials: D
authors.lastname: Schmidt
authors.affiliation: Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba CEP 13418-900, Brazil.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Rizzi
authors.affiliation: Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba CEP 13418-900, Brazil.
authors.forename: Salete A
authors.initials: SA
authors.lastname: Gaziola
authors.affiliation: Departamento de Ciências Fisiológicas, Universidade Federal Rural do Rio de Janeiro, Seropédica CEP 23890-000, Brazil.
authors.forename: Leonardo O
authors.initials: LO
authors.lastname: Medici
authors.affiliation: Faculty of Agricultural Sciences, Department of Genetics and Biotechnology, Research Centre Flakkebjerg, University of Aarhus, Forsoegsvej 1, DK-4200 Slagelse, Denmark.
authors.forename: Eva
authors.initials: E
authors.lastname: Vincze
authors.affiliation: Department of Botany, Warsaw University of Life Sciences - SGGW, Nowoursynowska 159, 02-766 Warsaw, Poland.
authors.forename: Marcin
authors.initials: M
authors.lastname: Kozak
authors.affiliation: Lancaster Environment Centre, University of Lancaster, Lancaster LA1 4YQ, United Kingdom.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Lea
authors.affiliation: Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba CEP 13418-900, Brazil. Electronic address: raa@usp.br.
authors.forename: Ricardo A
authors.initials: RA
authors.lastname: Azevedo
mesh_terms: D016373:DNA, Antisense; D005983:Glutens; D001467:Hordeum / Q000235:genetics / Q000378:metabolism*; D008239:Lysine / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism*
chemical_list: D016373:DNA, Antisense; D005983:Glutens; D008239:Lysine
keywords: Aspartate kinase; Dihydrodipicolinate synthase; Homoserine dehydrogenase; Lysine; Lysine α-ketoglutarate reductase; Saccharopine dehydrogenase