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Two closely linked tomato HKT coding genes are positional candidates for the major tomato QTL involved in N a + / K + homeostasis
Control of intracellular Na + and K + concentrations in plant tissues under saline conditions is crucial for salt tolerance. In this study, two Na + ‐selective class I ‐ HKT transporters, HKT 1;1 and HKT 1;2, from tomato were found to be closely linked in proximity to the position with the maximum L...
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Published in: | Plant, cell and environment cell and environment, 2013-06, Vol.36 (6), p.1171-1191 |
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Main Authors: | , , , , , , , , , , , |
Format: | Article |
Language: | English |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Control of intracellular
Na
+
and
K
+
concentrations in plant tissues under saline conditions is crucial for salt tolerance. In this study, two
Na
+
‐selective class
I
‐
HKT
transporters,
HKT
1;1 and
HKT
1;2, from tomato were found to be closely linked in proximity to the position with the maximum
LOD
score for major
QTLs
in chromosome 7 (at a distance of 35 kb), thus contributing to stem and leaf
Na
+
and
K
+
in two populations of tomato
RILs
derived from two salt‐tolerant lines from wild tomato species
S
. pimpinellifolium
and
S
. cheesmaniae
. This result, together with their patterns of expression and phenotypic effects on a pair of near isogenic lines (
NILs
) differing in terms of HKT1‐like alleles, support the hypothesis that
HKT
1;1
and/or
HKT
1;2
genes underlies a major tomato
QTL
for shoot
Na
+
/
K
+
.
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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ISSN: | 0140-7791 1365-3040 |
DOI: | 10.1111/pce.12051 |