title: C4 isoform of NADP-malate dehydrogenase. cDNA cloning and expression in leaves of C4, C3, and C3-C4 intermediate species of Flaveria.
abstract: In C4 plants of the NADP-malic enzyme type, an abundant, mesophyll cell-localized NADP-malate dehydrogenase (MDH) acts to convert oxaloacetate, the initial product of carbon fixation, to malate before it is shuttled to the bundle sheath. Since NADP-MDH has different but important roles in leaves of C3 and C4 plants, we have cloned and characterized a nearly full-length cDNA encoding NADP-MDH from Flaveria trinervia (C4) to permit comparative structure/expression studies within the genus flaveria. The dicot genus Flaveria includes C3-C4 intermediate species, as well as C3 and C4 species. We show that the previously noted differences in NADP-MDH activity levels among C3, C4, and C3-C4 Flaveria species are in part due to interspecific differences in mRNA accumulation. We also show that the NADP-MDH gene appears to be present as a single copy among different Flaveria species, suggesting that a pre-existing gene has been reregulated during the evolution from C3 to C4 plants to accommodate the abundance and localization requirements of the C4 cycle.
authors.affiliation: Department of Biology, Yale University, New Haven, Connecticut 06520-8104, USA.
authors.forename: B
authors.initials: B
authors.lastname: McGonigle
authors.forename: T
authors.initials: T
authors.lastname: Nelson
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary; D018744:DNA, Plant; D007527:Isoenzymes / Q000235:genetics*; D008291:Malate Dehydrogenase / Q000235:genetics*; D050538:Malate Dehydrogenase (NADP+); D008969:Molecular Sequence Data; D018515:Plant Leaves / Q000378:metabolism; D010944:Plants / Q000201:enzymology / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
chemical_list: D018076:DNA, Complementary; D018744:DNA, Plant; D007527:Isoenzymes; D012333:RNA, Messenger; D008291:Malate Dehydrogenase; D050538:Malate Dehydrogenase (NADP+)