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ARS Home » Plains Area » El Reno, Oklahoma » Oklahoma and Central Plains Agricultural Research Center » Peanut and Small Grains Research Unit » Research » Publications at this Location » Publication #407880
Research Project: Genetic Mechanisms and Improvement of Insect Resistance in Wheat, Barley, and Sorghum

Location: Peanut and Small Grains Research Unit

Title: Identification of a new Rsg1 allele conferring resistance to multiple greenbug biotypes from barley accessions PI 499276 and PI 566459

Author
item Xu, Xiangyang
item Mornhinweg, Dolores - Do
item Bai, Guihua
item Li, Genqiao
item BIAN, RUOLIN - Kansas State University
item Bernardo, Amy
item Armstrong, John

Submitted to: The Plant Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/14/2023
Publication Date: 12/13/2023
Citation: Xu, X., Mornhinweg, D.W., Bai, G., Li, G., Bian, R., Bernardo, A.E., Armstrong, J.S. 2023. Identification of a new Rsg1 allele conferring resistance to multiple greenbug biotypes from barley accessions PI 499276 and PI 566459. The Plant Genome. https://doi.org/10.1002/tpg2.20418.
DOI: https://doi.org/10.1002/tpg2.20418

Interpretive Summary: Greenbug [Schizaphis graminum (Rondani)] is a major insect pest that significantly reduces barley production worldwide. Identification of novel greenbug resistance genes is crucial for sustainable barley production and global food security. The U.S. breeding line PI 499276 and Chinese cultivar PI 566459 exhibit resistance to greenbug biotypes B, E, F, I, WY10 MC, and WY10B. The objective of this study was to reveal the gene identities in PI 499276 and PI 566459. Two recombinant inbred line (RIL) populations were developed from crosses Weskan × PI 499276 and Weskan × PI 566459, and were evaluated for responses to greenbug biotype E. The two populations were genotyped using SNP markers. Linkage analyses using phenotypic data and SNP marker data identified a single dominant gene from PI 499276 and PI 566459, and this gene was mapped in a 1.2 Mb genomic region between 666.5 and 667.7 Mb on the long arm of chromosome 7H in the Morex Hordeum vulgare r1 reference sequence. This gene is a new Rsg1 allele, designated as Rsg1.a2. High throughput KASP markers were developed to rapidly transfer Rsg1.a2 into elite barley cultivars.

Technical Abstract: Greenbug [Schizaphis graminum (Rondani)] is a major insect pest that significantly reduces barley production worldwide. Identification of novel greenbug resistance genes is crucial for sustainable barley production and global food security. To identify greenbug resistance genes from a U.S. breeding line PI 499276 and a Chinese cultivar PI 566459, two F6:7 recombinant inbred line (RIL) populations developed from crosses Weskan × PI 499276 and Weskan × PI 566459 were phenotyped for responses to greenbug biotype E and genotyped using genotyping-by-sequencing (GBS). GBS analysis identified 2811 and 1702 high quality single nucleotide polymorphism (SNP) marker in the Weskan × PI 499276 and Weskan × PI 566459 populations, respectively. Some GBS-SNPs in the target gene regions were converted into kompetitive allele-specific polymorphism (KASP) markers and used to genotype the RIL populations. Linkage analysis delimited the greenbug resistance genes from PI 499276 and PI 566459 to a 1.2 Mb genomic region between 666.5 and 667.7 Mb on the long arm of chromosome 7H in the Morex Hordeum vulgare r1 reference sequence. Allelism tests based on responses of four F2 populations to greenbug biotype E indicated that the greenbug resistance gene in PI 499276 and PI 566459 is either allelic or very close to Rsg1. Given that PI 499276 and PI 566459 shared the same unique resistance pattern to a set of 14 greenbug biotypes, which is different from those of other Rsg1 alleles, they carry a new Rsg1 allele, designated Rsg1.a2. KASP markers KASP-1a3-1, KASP-1a3-2, and KASP160 can be used to tag Rsg1.a2 in barley breeding.