title: Cloning and endogenous expression of a Eucalyptus grandis UDP-glucose dehydrogenase cDNA.
abstract: UDP-glucose dehydrogenase (UGDH) catalyzes the oxidation of UDP-glucose (UDP-Glc) to UDP-glucuronate (UDP-GlcA), a key sugar nucleotide involved in the biosynthesis of plant cell wall polysaccharides. A full-length cDNA fragment coding for UGDH was cloned from the cambial region of 6-month-old E. grandis saplings by RT-PCR. The 1443-bp-ORF encodes a protein of 480 amino acids with a predicted molecular weight of 53 kDa. The recombinant protein expressed in Escherichia coli catalyzed the conversion of UDP-Glc to UDP-GlcA, confirming that the cloned cDNA encodes UGDH. The deduced amino acid sequence of the cDNA showed a high degree of identity with UGDH from several plant species. The Southern blot assay indicated that more than one copy of UGDH is present in Eucalyptus. These results were also confirmed by the proteomic analysis of the cambial region of 3- and 22-year-old E. grandis trees by 2-DE and LC-MS/MS, showing that at least two isoforms are present. The cloned gene is mainly expressed in roots, stem and bark of 6-month-old saplings, with a lower expression in leaves. High expression levels were also observed in the cambial region of 3- and 22-year-old trees. The results described in this paper provide a further view of the hemicellulose biosynthesis during wood formation in E. grandis.
authors.affiliation: Laboratório Max Feffer de Genética de Plantas, Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, SP Brazil.
authors.forename: Mônica T Veneziano
authors.initials: MT
authors.lastname: Labate
authors.forename: Ana L Ferreira
authors.initials: AL
authors.lastname: Bertolo
authors.forename: Daniela Defávari
authors.initials: DD
authors.lastname: do Nascimento
authors.forename: Gunta
authors.initials: G
authors.lastname: Gutmanis
authors.forename: Alexander
authors.initials: A
authors.lastname: de Andrade
authors.forename: Maria J Calderan
authors.initials: MJ
authors.lastname: Rodrigues
authors.forename: Eduardo L O
authors.initials: EL
authors.lastname: Camargo
authors.forename: Luis Felipe
authors.initials: LF
authors.lastname: Boaretto
authors.forename: David H
authors.initials: DH
authors.lastname: Moon
authors.forename: Juliano
authors.initials: J
authors.lastname: Bragatto
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Labate