title: Molecular characterization of the citrate transporter gene TaMATE1 and expression analysis of upstream genes involved in organic acid transport under Al stress in bread wheat (Triticum aestivum).
abstract: In bread wheat, besides malate, the importance of citrate efflux for Al tolerance has also been reported. For better understanding the Al tolerance mechanism in bread wheat, here, we performed both a molecular characterization of the citrate transporter gene TaMATE1 and an investigation on the upstream variations in citrate and malate transporter genes. TaMATE1 belong to multidrug transporter protein family, which are located on the long arm of homoeologous group 4 chromosomes (TaMATE1-4A, TaMATE1-4B TaMATE1-4D). TaMATE1 homoeologues transcript expression study exhibited the preponderance of homoeologue TaMATE1-4B followed by TaMATE1-4D whereas homoeologue TaMATE1-4A seemed to be silenced. TaMATE1, particularly homoeologue TaMATE1-4B and TaALMT1 transcripts were much more expressed in the root apices than in shoots of Al tolerant genotype Barbela 7/72/92 under both control and Al stress conditions. In addition, in both tissues of Barbela 7/72/92, higher basal levels of these gene transcripts were observed than in Anahuac (Al sensitive). Noticeably, the presence of a transposon in the upstream of TaMATE1-4B in Barbela 7/72/92 seems to be responsible for its higher transcript expression where it may confer citrate efflux. Thus, promoter variations (transposon in TaMATE1-4B upstream and type VI promoter in TaALMT1) associated with higher basal transcript expression of TaMATE1-4B and TaALMT1 clearly show how different mechanisms for Al tolerance operate simultaneously in a single genotype. In conclusion, our results demonstrate that Barbela 7/72/92 has favorable alleles for these organic acids transporter genes which could be utilized through genomic assisted selection to develop improved cultivars for acidic soils.
authors.affiliation: Centro de Genómica e Biotecnologia, Instituto de Biotecnologia e Bioengenharia (CGB/IBB), Universidade de Trás-os-Montes e Alto Douro (UTAD), PO Box 1013, 5001-801, Vila Real, Portugal; Departamento de Genética, Facultad de Biología, Universidad Complutense de Madrid (UCM), 28040 Madrid, Spain.
authors.forename: Ana Luísa
authors.initials: AL
authors.lastname: Garcia-Oliveira
authors.forename: Paula
authors.initials: P
authors.lastname: Martins-Lopes
authors.forename: Roser
authors.initials: R
authors.lastname: Tolrá
authors.forename: Charlotte
authors.initials: C
authors.lastname: Poschenrieder
authors.forename: Marta
authors.initials: M
authors.lastname: Tarquis
authors.forename: Henrique
authors.initials: H
authors.lastname: Guedes-Pinto
authors.forename: César
authors.initials: C
authors.lastname: Benito
mesh_terms: D000483:Alleles; D000535:Aluminum / Q000633:toxicity; D001483:Base Sequence; D001692:Biological Transport; D002264:Carboxylic Acids / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D019343:Citric Acid / Q000378:metabolism*; D005838:Genotype; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D018520:Plant Shoots / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics*; D017422:Sequence Analysis, DNA; D013312:Stress, Physiological; D014908:Triticum / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism
chemical_list: D002264:Carboxylic Acids; D002352:Carrier Proteins; D010940:Plant Proteins; C020723:citrate-binding transport protein; D019343:Citric Acid; D000535:Aluminum