Greenbug (Schizaphis graminum Rondani) is a destructive insect pest that not only damages plants, but also serves as a vector for many viruses. Host plant resistance is the preferred strategy for managing greenbug. To date, only two greenbug resistance genes, Rsg1 and Rsg2, have been reported in barley, with only the former being deployed in cultivars. To breed cultivars with effective resistance against various greenbug biotypes, additional resistance genes are urgently needed to sustain barley production. Wild barley accession WBDC053 (PI 681777), originating from the Baluchistan region of Pakistan, was previously found to be resistant to several greenbug biotypes. In this study, a recombinant inbred line (RIL) population derived from Weskan × WBDC053 was evaluated for response to greenbug biotype E and genotyped using genotyping by sequencing (GBS). A set of 3,347 high quality GBS-derived single nucleotide polymorphisms (SNPs) were then used to map a greenbug resistance gene in this wild barley accession. Linkage analysis placed the greenbug resistance gene in WBDC053, temporarily designated RsgWBDC053, in a 2.35 Mb interval (0-2,354,645 bp) in the terminal region of the short arm of chromosome 2H. This interval harbors 15 genes with leucine-rich-repeat (LRR) protein domains. An allelism test between WBDC053 carrying RsgWBDC053 and STARS1501B carrying Rsg2 indicated that the former is either allelic or closely linked to the latter. GBS-SNPs 2H_1318811 and 2H_1839499 co-segregated with RsgWBDC053 and were converted to Kompetitive allele specific PCR (KASP) markers, KASP-Rsg053-1 and KASP-Rsg0533-2. The two KASP markers can be used to select for RsgWBDC053, but also have the potential to tag Rsg2 in barley improvement programs.

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Posted 17 May, 2021
Posted 17 May, 2021
Greenbug (Schizaphis graminum Rondani) is a destructive insect pest that not only damages plants, but also serves as a vector for many viruses. Host plant resistance is the preferred strategy for managing greenbug. To date, only two greenbug resistance genes, Rsg1 and Rsg2, have been reported in barley, with only the former being deployed in cultivars. To breed cultivars with effective resistance against various greenbug biotypes, additional resistance genes are urgently needed to sustain barley production. Wild barley accession WBDC053 (PI 681777), originating from the Baluchistan region of Pakistan, was previously found to be resistant to several greenbug biotypes. In this study, a recombinant inbred line (RIL) population derived from Weskan × WBDC053 was evaluated for response to greenbug biotype E and genotyped using genotyping by sequencing (GBS). A set of 3,347 high quality GBS-derived single nucleotide polymorphisms (SNPs) were then used to map a greenbug resistance gene in this wild barley accession. Linkage analysis placed the greenbug resistance gene in WBDC053, temporarily designated RsgWBDC053, in a 2.35 Mb interval (0-2,354,645 bp) in the terminal region of the short arm of chromosome 2H. This interval harbors 15 genes with leucine-rich-repeat (LRR) protein domains. An allelism test between WBDC053 carrying RsgWBDC053 and STARS1501B carrying Rsg2 indicated that the former is either allelic or closely linked to the latter. GBS-SNPs 2H_1318811 and 2H_1839499 co-segregated with RsgWBDC053 and were converted to Kompetitive allele specific PCR (KASP) markers, KASP-Rsg053-1 and KASP-Rsg0533-2. The two KASP markers can be used to select for RsgWBDC053, but also have the potential to tag Rsg2 in barley improvement programs.

Figure 1

Figure 2
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