Forskning ved Københavns Universitet - Københavns Universitet


Molecular characterization and expression studies during melon fruit development and ripening of L-galactono-1,4-lactone dehydrogenase

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  • Irene Pateraki
  • Maite Sanmartin
  • Mary S. Kalamaki
  • Dimitrios Gerasopoulos
  • Angelos K. Kanellis
  • Pateraki, Irini

The last step of ascorbic acid (AA) biosynthesis is catalysed by the enzyme L-galactono-1,4-lactone dehydrogenase (GalLDH, EC, located on the inner mitochondrial membrane. The enzyme converts L-galactono-1,4-lactone to ascorbic acid (AA). In this work, the cloning and characterization of a GalLDH full-length cDNA from melon (Cucumis melo L.) are described. Melon genomic DNA Southern analysis indicated that CmGalLDH was encoded by a single gene. CmGalLDH mRNA accumulation was detected in all tissues studied, but differentially expressed during fruit development and seed germination. It is hypothesized that induction of CmGalLDH gene expression in ripening melon fruit contributes to parallel increases in the AA content and so playing a role in the oxidative ripening process. Higher CmGalLDH message abundance in light-grown seedlings compared with those raised in the dark suggests that CmGalLDH expression is regulated by light. Finally, various stresses and growth regulators resulted in no significant change in steady state levels of CmGalLDH mRNA in 20-d-old melon seedlings. To the authors' knowledge, this is the first report of GalLDH transcript induction in seed germination and differential gene expression during fruit ripening.

TidsskriftJournal of Experimental Botany
Udgave nummer403
Sider (fra-til)1623-1633
Antal sider11
StatusUdgivet - 1 aug. 2004

ID: 131465558