title: Two closely linked tomato HKT coding genes are positional candidates for the major tomato QTL involved in Na+ /K+ homeostasis.
abstract: The location of major quantitative trait loci (QTL) contributing to stem and leaf [Na(+) ] and [K(+) ] was previously reported in chromosome 7 using two connected populations of recombinant inbred lines (RILs) of tomato. HKT1;1 and HKT1;2, two tomato Na(+) -selective class I-HKT transporters, were found to be closely linked, where the maximum logarithm of odds (LOD) score for these QTLs located. When a chromosome 7 linkage map based on 278 single-nucleotide polymorphisms (SNPs) was used, the maximum LOD score position was only 35 kb from HKT1;1 and HKT1;2. Their expression patterns and phenotypic effects were further investigated in two near-isogenic lines (NILs): 157-14 (double homozygote for the cheesmaniae alleles) and 157-17 (double homozygote for the lycopersicum alleles). The expression pattern for the HKT1;1 and HKT1;2 alleles was complex, possibly because of differences in their promoter sequences. High salinity had very little effect on root dry and fresh weight and consequently on the plant dry weight of NIL 157-14 in comparison with 157-17. A significant difference between NILs was also found for [K(+) ] and the [Na(+) ]/[K(+) ] ratio in leaf and stem but not for [Na(+) ] arising a disagreement with the corresponding RIL population. Their association with leaf [Na(+) ] and salt tolerance in tomato is also discussed.
authors.affiliation: Plant Protection and Biotechnology Center, Instituto Valenciano de Investigaciones Agrarias (IVIA), E46113, Valencia, Spain. mjasins@ivia.es
authors.forename: Maria José
authors.initials: MJ
authors.lastname: Asins
authors.forename: Irene
authors.initials: I
authors.lastname: Villalta
authors.forename: Mohamed M
authors.initials: MM
authors.lastname: Aly
authors.forename: Raquel
authors.initials: R
authors.lastname: Olías
authors.forename: Paz
authors.initials: P
authors.lastname: Alvarez DE Morales
authors.forename: Raúl
authors.initials: R
authors.lastname: Huertas
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Noelia
authors.initials: N
authors.lastname: Jaime-Pérez
authors.forename: Rosario
authors.initials: R
authors.lastname: Haro
authors.forename: Verónica
authors.initials: V
authors.lastname: Raga
authors.forename: Emilio A
authors.initials: EA
authors.lastname: Carbonell
authors.forename: Andrés
authors.initials: A
authors.lastname: Belver
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D027682:Cation Transport Proteins / Q000235:genetics* / Q000378:metabolism; D032461:Chromosomes, Plant; D005816:Genetic Complementation Test; D006706:Homeostasis / Q000235:genetics; D018551:Solanum lycopersicum / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011188:Potassium / Q000502:physiology*; D040641:Quantitative Trait Loci; D017422:Sequence Analysis, DNA; D012964:Sodium / Q000502:physiology*; D027981:Symporters / Q000235:genetics* / Q000378:metabolism
chemical_list: D027682:Cation Transport Proteins; C088864:HKT1 protein, plant; D010940:Plant Proteins; D027981:Symporters; D012964:Sodium; D011188:Potassium