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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 #417357
Research Project: Genetic Improvement for Resistance to Aphids and Major Diseases in Wheat, Barley, and Sorghum in the Great Plains

Location: Peanut and Small Grains Research Unit

Title: Characterization of a new barley greenbug resistance gene Rsg4 in the Chinese landrace CI 2458

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

Submitted to: The Plant Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/15/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Barley (Hordeum vulgare) is a climate resilient crop widely cultivated in both highly productive and suboptimal agricultural systems. Annual yield loss of barley to insect pests is 8.8% worldwide. Greenbug is a major destructive insect pest in barley. Although resistance to greenbug is available for currently prevalent biotypes, the occurrence of biotype shifts, common in aphids, necessitates novel greenbug resistance genes to overcome the challenges posed by newly emerging greenbug biotypes. CI 2458 is a landrace exhibiting a unique resistance profile to a set of 14 greenbug biotypes, suggesting the presence of a new greenbug resistance gene in CI 2458. Genetic analysis indicated that the greenbug resistance gene in CI 2458, designated Rsg4, resides in the terminal region of chromosome arm 3HL. Rsg4 differs from other geenbug resistance genes located in 3HL in its resistance to greenbug biotype TX1, which is virulent to other resistance genes in 3HL. Rsg4 is a valuable source of resistance to greenbug, and the user-friendly, high throughput molecular markers developed in this study enable rapid introgression of Rsg4 into locally adapted cultivars.

Technical Abstract: Barley (Hordeum vulgare) is a climate resilient crop widely cultivated in both highly productive and suboptimal agricultural systems, and its ability to adapt to multiple biotic and abiotic stresses has contributed significantly to food security. Greenbug is a destructive insect pest for global barley production and new greenbug resistance genes are needed to overcome the challenges posed by diverse greenbug biotypes in fields. CI 2458 is a Chinese landrace exhibiting a unique resistance profile to a set of 14 greenbug biotypes, which suggests the presence of a new greenbug resistance gene in CI 2458. A recombinant inbred line (RIL) population from cross Weskan × CI 2458 was developed, evaluated for responses to greenbug biotype E and genotyped using single nucleotide polymorphism (SNP) markers generated by genotyping-by-sequencing (GBS). Linkage analysis revealed a single gene, designated Rsg4, conditioning greenbug resistance in CI 2458. Rsg4 was delimited to a 1.14 Mb-interval between SNP markers S3H_666512114 and S3H_667651446 in the terminal region of chromosome arm 3HL, with genetic distances of 1.2 cM proximal to S3H_667651446 and 1.1 cM distal to S3H_666512114. Allelism tests confirmed that Rsg4 is a new greenbug resistance gene independent of Rsg1 and Rsg3 which reside in the same chromosome arm. Rsg4 differs from Rsg1 alleles and Rsg3 in its resistance to greenbug biotype TX1, one of the most widely virulent biotypes. The introgression of Rsg4 into locally adapted barley cultivars is of agronomic importance and KASP markers flanking Rsg4, KASP-Rsg336-1 and KASP-Rsg336-2, enable rapid pyramiding Rsg4 with other resistance genes to develop durable greenbug resistant cultivars.