Two closely linked tomato HKT coding genes are positional candidates for the major tomato QTL involved in Na+/K+ homeostasis |
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Authors: | MARIA JOSÉ ASINS IRENE VILLALTA MOHAMED M ALY RAQUEL OLÍAS PAZ ÁLVAREZ DE MORALES RAÚL HUERTAS JUN LI NOELIA JAIME‐PÉREZ ROSARIO HARO VERÓNICA RAGA EMILIO A CARBONELL ANDRÉS BELVER |
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Institution: | 1. Plant Protection and Biotechnology Center, Instituto Valenciano de Investigaciones Agrarias (IVIA), , E46113 Valencia, Spain;2. Department of Biochemistry, Molecular and Cellular Biology of Plants, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas (CSIC), , E‐18008 Granada, Spain;3. Center for Plant Biotechnology and Genomics (UPM‐INIA), Universidad Politécnica de Madrid, , E28223 Madrid, Spain |
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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. |
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Keywords: | Solanum cheesmaniae Solanum lycopersicum candidate gene analysis HKT1‐like genes K+ and Na+ concentration |
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