|QURESHI, NAEELA - University Of Sydney|
|BARIANA, HARBANS - University Of Sydney|
|Kolmer, James - Jim|
|MIAH, HANF - University Of Sydney|
|URMIL, BANSAL - University Of Sydney|
Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/13/2017
Publication Date: 11/1/2017
Citation: Qureshi, N., Bariana, H., Kolmer, J.A., Miah, H., Urmil, B. 2017. Genetic and molecular characterization of leaf rust resistance in two durum landraces against the durum-specific Puccinia triticina races. Phytopathology. 107:1381-1387.
Interpretive Summary: Wheat is attacked by the leaf rust fungus, Puccinia triticina. Genes in wheat can provide resistance to this important pathogen and disease of wheat. Two durum wheat cultivars were characterized using DNA markers to determine the chromosome location of a leaf rust resistance gene. Both cultivars had the same gene located on the short arm of chromosome 6B. Molecular DNA markers that are easy for wheat breeders to use to select wheat cultivars with this gene were also developed. The markers will help wheat breeders add this gene to wheat cultivars for improved leaf rust resistance.
Technical Abstract: The Portuguese durum landraces, Aus26582 and Aus26579, showed resistance against two very different durum-specific Puccinia triticina (Pt) races CA 1.2 and ETH 12.5-2 collected from California and Ethiopia, respectively. Aus26582 and Aus26579 were crossed with a susceptible landrace Bansi to develop recombinant inbred line (RIL) F5:6 populations. Monogenic segregation for leaf rust response was observed in both RIL populations against Pt races CA 1.2 and ETH 12.5-2. Based on the identical phenotypic response and the same origin of both landraces, the underlying locus was temporarily named LrAW2. LrAW2 was integrated into the Aus26582/Bansi DArTseq map and it mapped to the short arm of chromosome 6B. Five markers that co-segregated with LrAW2 were BlastN searched against the wheat chromosome survey sequence (CSS) contigs. Simple sequence repeat (SSR) markers sun683 and sun684, developed from the CSS contig 6BS_2963854, co-segregated with LrAW2. Sequence-tagged-site (STS) primers were developed from the whole CSS contig 6BS_2963854 to amplify >1Kb amplicons in the parental genotypes Aus26582 and Bansi and sequencing of these amplicons identified single nucleotide polymorphisms (SNPs). The allele specific marker sunKASP_60 mapped 0.2 cM and 0.6 cM proximal to LrAW2 in Aus26582/Bansi and Aus26579/Bansi RIL populations, respectively. Based on the genomic location and the similar results with LrAW2-linked markers for Aus26582, Aus26579 and Guayacan, LrAW2 was concluded to be Lr61. The amplification of sun683, sun684 and sunKASP_60 products different to that linked with Lr61 among Australian durum cultivars demonstrated their robustness in marker-assisted selection.