Development and validation of KASP markers for the greenbug resistance gene Gb7 and the Hessian fly resistance gene H32 in wheat

Authors: TAN, CHOR-TEE - TEXAS A&M AGRILIFE; YU, HANGJIN - TEXAS A&M AGRILIFE; YANG, YAN - TEXAS A&M UNIVERSITY; Xu, Xiangyang; Chen, Ming-Shun; RUDD, JACKIE - TEXAS A&M AGRILIFE; XUE, QUINGWU - TEXAS A&M AGRILIFE; IBRAHIM, AMIR - TEXAS A&M UNIVERSITY; GARZA, LISA - TEXAS A&M AGRILIFE; WANG, SHICHEN - TEXAS A&M UNIVERSITY; SORRELLS, MARK - CORNELL UNIVERSITY; LIU, SHUYU - TEXAS A&M AGRILIFE

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2017
Publication Date: 8/25/2017
Citation: Tan, C., Yu, H., Yang, Y., Xu, X., Chen, M., Rudd, J.C., Xue, Q., Ibrahim, A., Garza, L., Wang, S., Sorrells, M.E., Liu, S. 2017. Development and validation of KASP markers for the greenbug resistance gene Gb7 and the Hessian fly resistance gene H32 in wheat. Theoretical and Applied Genetics. 130(9):1867-1884.

Interpretive Summary: Greenbug (GB) and Hessian fly (HF) are two major wheat pests throughout wheat production regions of the United States. GB and HF infestation can significantly reduce grain yield, and growing resistant cultivars is the most feasible strategy to reduce losses caused by GB and HF. Marker-assisted selection of GB and HF resistance is a desirable method in pest resistance breeding. A doubled haploid (DH) population derived from a cross "Synthetic W7984 × OpataM85" was employed to construct linkage maps using single nucleoid polymorphism (SNP) markers. Four SNP markers closely linked to the Gb7 and H32 genes were identified, and further converted to Kompetitve Allele-Specific PCR (KASP) markers. These markers can be easily used in marker-assisted breeding to accurately select plants carrying these genes.

Technical Abstract: Greenbug (GB, Schizaphis graminum Rondani) and Hessian fly [HF, Mayetiola destructor (Say)] are two major destructive insect pests of wheat (Triticum aestivum L) throughout wheat production regions of the United States and worldwide. GB and HF infestation can significantly reduce grain yield and quality. Breeding for wheat cultivars with resistance is the most feasible strategy to minimize losses. Application of breeder-friendly and high-throughput markers for marker-assisted selection (MAS) of GB and HF resistance will enhance breeding selection and cultivar development. In this study, doubled haploid lines derived from the Synthetic W7984 × OpataM85 wheat reference population were used to construct linkage maps for GB resistance gene Gb7 and HF resistance gene H32 with genotyping-by-sequencing (GBS) and 90K array-based SNP marker data. SNP markers closely flanking the Gb7 gene on chromosome 7DL and the H32 gene on chromosome 3DL were identified. Two Gb7-linked markers (synopGBS773 and synopGBS1141) and two H32-linked markers (synopGBS901 and IWB65911) were converted into Kompetitve Allele-Specific PCR (KASP) assays for MAS in wheat breeding. In addition, comparative mapping was performed using sequences of GBS and SNP markers flanking Gb7 and H32, leading to the identification of syntenic regions in Brachypodium and rice for future fine mapping and map-based cloning of the genes. The KASP markers developed in this study should be useful for MAS of Gb7 and H32 in wheat breeding programs, as well as future genetic studies of GB and HF resistance.