title: Characterization of mitochondrial dicarboxylate/tricarboxylate transporters from grape berries.
abstract: Grape berries (Vitis vinifera L fruit) exhibit a double-sigmoid pattern of development that results from two successive periods of vacuolar swelling during which the nature of accumulated solutes changes significantly. Throughout the first period, called green or herbaceous stage, berries accumulate high levels of organic acids, mainly malate and tartrate. At the cellular level fruit acidity comprises both metabolism and vacuolar storage. Malic acid compartmentation is critical for optimal functioning of cytosolic enzymes. Therefore, the identification and characterization of the carriers involved in malate transport across sub-cellular compartments is of great importance. The decrease in acid content during grape berry ripening has been mainly associated to mitochondrial malate oxidation. However, no Vitis vinifera mitochondrial carrier involved in malate transport has been reported to date. Here we describe the identification of three V. vinifera mitochondrial dicarboxylate/tricarboxylate carriers (VvDTC1-3) putatively involved in mitochondrial malate, citrate and other di/tricarboxylates transport. The three VvDTCs are very similar, sharing a percentage of identical residues of at least 83 %. Expression analysis of the encoding VvDTC genes in grape berries shows that they are differentially regulated exhibiting a developmental pattern of expression. The simultaneous high expression of both VvDTC2 and VvDTC3 in grape berry mesocarp close to the onset of ripening suggests that these carriers might be involved in the transport of malate into mitochondria.
authors.affiliation: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República-EAN, 2780-157, Oeiras, Portugal. regalado@itqb.unl.pt
authors.forename: Ana
authors.initials: A
authors.lastname: Regalado
authors.forename: Ciro Leonardo
authors.initials: CL
authors.lastname: Pierri
authors.forename: Maria
authors.initials: M
authors.lastname: Bitetto
authors.forename: Valentina Liliana
authors.initials: VL
authors.lastname: Laera
authors.forename: Catarina
authors.initials: C
authors.lastname: Pimentel
authors.forename: Rita
authors.initials: R
authors.lastname: Francisco
authors.forename: José
authors.initials: J
authors.lastname: Passarinho
authors.forename: Maria M
authors.initials: MM
authors.lastname: Chaves
authors.forename: Gennaro
authors.initials: G
authors.lastname: Agrimi
mesh_terms: D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D003001:Cloning, Molecular; D029382:Dicarboxylic Acid Transporters / Q000737:chemistry / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism; D005638:Fruit / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D007700:Kinetics; D008293:Malates / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011994:Recombinant Proteins / Q000378:metabolism; D016415:Sequence Alignment; D013379:Substrate Specificity; D027843:Vitis / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D029382:Dicarboxylic Acid Transporters; D008293:Malates; D011994:Recombinant Proteins; C020723:citrate-binding transport protein; C030298:malic acid