Characterization of wheat curl mite resistance gene Cmc4 in OK05312

Authors: ZHAO, LANFEI - Kansas State University; LIU, SHUYU - Texas A&M University; ABDELSALAM, NADER - Kansas State University; CARVAR, BRETT - Oklahoma State University; Bai, Guihua

Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/18/2020
Publication Date: 2/19/2021
Citation: Zhao, L., Liu, S., Abdelsalam, N., Carvar, B., Bai, G. 2021. Characterization of wheat curl mite resistance gene Cmc4 in OK05312. Journal of Theoretical and Applied Genetics. 134:993–1005. https://doi.org/10.1007/s00122-020-03737-3.
DOI: https://doi.org/10.1007/s00122-020-03737-3

Interpretive Summary: Wheat curl mite (WCM) is a serious wheat pest worldwide because it can carry several important wheat viruses. A wheat line named OK05312 carries the Cmc4 resistance gene to WCM. Previously we mapped the gene on the short arm of chromosome 6D. In this study, we further defined Cmc4 in OK05312 to a small genomic region of approximately 523 kb in length. We developed breeder-friendly DNA markers that are close to Cmc4 for diagnosing the presence of Cmc4 in wheat breeding lines. Our results also suggested that Cmc4 in OK05312 and CmcTAM112 in cultivar TAM112 might be the same gene.

Technical Abstract: Wheat curl mite (WCM, Aceria tosichella Keifer) is a disastrous wheat pest in many wheat-growing regions worldwide. WCM not only directly affects wheat yield, but also transmits wheat streak mosaic virus (WSMV). Growing WCM resistant cultivars is the most economical and sustainable method to reduce its damage. A hard winter wheat breeding line OK05312 (PI 670019) carries Cmc4 gene resistance to A. tosichella and has many desirable agronomic traits. To finely map Cmc4 in OK05312, two recombinant inbred line (RIL) populations were developed from crosses between OK05312 and two susceptible cultivars, SD06165 and Jerry, genotyped using single nucleotide polymorphism (SNP) markers generated from genotyping-by-sequencing (GBS), and phenotyped for WCM resistance. Gene mapping using the two SNP maps confirmed Cmc4 in OK05312 that explained up to 68% of the phenotypic variation. Further analysis delimited Cmc4 to a ~523 kb region between SNPs SDOKSNP6314 and SDOKSNP2805 based on the Ae. tauschii reference genome. We developed 18 polymorphic Kompetitive Allele Specific PCR (KASP) markers using the sequences of GBS-SNPs in this region and 23 KASP markers based on the SNPs between the parents derived from 90K SNP chips. The KASP markers SDOKSNP6314 and SDOKSNP9699 are closest to Cmc4 and can be used to diagnose the presence of Cmc4 in wheat breeding programs. Haplotype analysis suggested that CmcTAM112 in TAM112 might be the same gene as Cmc4.