Fine Mapping of Lr49 Using 90K SNP Chip Array and Flow-Sorted Chromosome Sequencing in Wheat
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Date
2020
Journal Title
Journal ISSN
Volume Title
Publisher
Frontiers in Plant Science
Abstract
Leaf rust, caused by Puccinia triticina, threatens global wheat production due to the
constant evolution of virulent pathotypes that defeat commercially deployed all stageresistance
(ASR) genes in modern cultivars. Hence, the deployment of combinations of
adult plant resistance (APR) and ASR genes in new wheat cultivars is desirable. Adult plant
resistance gene Lr49 was previously mapped on the long arm of chromosome 4B of
cultivar VL404 and flanked by microsatellite markers barc163 (8.1 cM) and wmc349 (10.1
cM), neither of which was sufficiently closely linked for efficient marker assisted selection.
This study used high-density SNP genotyping and flow sorted chromosome sequencing
to fine-map the Lr49 locus as a starting point to develop a diagnostic marker for use in
breeding and to clone this gene. Marker sunKASP_21 was mapped 0.4 cM proximal to
Lr49, whereas a group of markers including sunKASP_24 were placed 0.6 cM distal to
this gene. Testing of the linked markers on 75 Australian and 90 European cultivars with
diverse genetic backgrounds showed that sunKASP_21 was most strongly associated
with Lr49. Our results also show that the Lr49 genomic region contains structural variation
relative to the reference stock Chinese Spring, possibly an inverted genomic duplication,
which introduces a new set of challenges for the Lr49 cloning.
Description
Keywords
Adult plant resistance, Chromosome sorting, Infinium iSelect 90K SNP array, Leaf rust, Marker assisted breeding
Citation
Nsabiyera V, Baranwal D, Qureshi N, Kay P, Forrest K, Valárik M, Doležel J, Hayden MJ, Bariana HS and Bansal UK (2020) Fine Mapping of Lr49 Using 90K SNP Chip Array and Flow-Sorted Chromosome Sequencing in Wheat. Front. Plant Sci. 10:1787. doi: 10.3389/fpls.2019.01787