Genetic mapping of the wheat leaf rust resistance gene Lr19 and development of translocation lines to break its linkage with yellow pigment
Key message The leaf rust resistance gene Lr19 , which is present on the long arm of chromosome 7E1 in Thinopyrum ponticum , was mapped within a 0.3-cM genetic interval, and translocation lines were developed to break its linkage with yellow pigmentation The leaf rust resistance locus Lr19 , which w...
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Veröffentlicht in: | Theoretical and applied genetics 2023-09, Vol.136 (9), p.200-200, Article 200 |
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The leaf rust resistance gene
Lr19
, which is present on the long arm of chromosome 7E1 in
Thinopyrum ponticum
, was mapped within a 0.3-cM genetic interval, and translocation lines were developed to break its linkage with yellow pigmentation
The leaf rust resistance locus
Lr19
, which was transferred to wheat (
Triticum aestivum
) from its relative
Thinopyrum ponticum
in 1966, still confers broad resistance to most known races of the leaf rust pathogen
Puccinia triticina
(
Pt
) worldwide. However, this gene has not previously been fine-mapped, and its tight linkage with a gene causing yellow pigmentation has limited its application in bread wheat breeding. In this study, we genetically mapped
Lr19
using a bi-parental population from a cross of two wheat-
Th. ponticum
substitution lines, the
Lr19
-carrying line 7E1(7D) and the leaf rust-susceptible line 7E2(7D). Genetic analysis of the F
2
population and the F
2:3
families showed that
Lr19
was a single dominant gene. Genetic markers allowed the gene to be mapped within a 0.3-cM interval on the long arm of
Th. ponticum
chromosome 7E1, flanked by markers
XsdauK3734
and
XsdauK2839
. To reduce the size of the
Th. ponticum
chromosome segment carrying
Lr19
, the Chinese Spring
Ph1b
mutant was employed to promote recombination between the homoeologous chromosomes of the wheat chromosome 7D and the
Th. ponticum
chromosome 7E1. Two translocation lines with short
Th. ponticum
chromosome fragments carrying
Lr19
were identified using the genetic markers closely linked to
Lr19
. Both translocation lines were resistant to 16
Pt
races collected throughout China. Importantly, the linkage between
Lr19
and yellow pigment content was broken in one of the lines. Thus, the
Lr19
linked markers and translocation lines developed in this study are valuable resources in marker-assisted selection as part of common wheat breeding programs. |
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ISSN: | 0040-5752 1432-2242 |
DOI: | 10.1007/s00122-023-04425-8 |