Higher copy number of an Arachis hypogaea glutamate receptor-like candidate gene is associated with increased resistance to Tomato spotted wilt virus

Authors: WEBB, SYDNEY - University Of Georgia; CHU, YE - University Of Georgia; BISWAL, A - University Of Georgia; KORANI, WALID - Hudsonalpha Institute For Biotechnology; BOTTON, STEPHANIE - University Of Georgia; POKHREL, S - University Of Georgia; THOMPSON, E - Hudsonalpha Institute For Biotechnology; Guo, Baozhu; CULBREATH, ALBERT - University Of Georgia; CLEVENGER, JOSH - Hudsonalpha Institute For Biotechnology; Holbrook Jr, C; OZIAS-AKINS, PEGGY - University Of Georgia

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/8/2026
Publication Date: N/A
Citation: N/A

Interpretive Summary: Tomato Spotted Wilt Virus (TSWV) is one of the most destructive diseases of U.S. grown peanut. Although currently grown cultivars have a moderate level of resistance to TSWV. Higher levels of resistance are desirable. The objective of this study was to conduct genetic analysis of a new source of resistance, NC94022. Previous research had shown that the resistance in NC94022 was due to an insertion region, and molecular markers were designed for marker assisted selection. Eight populations derived from crosses with eight unique parents with a single recombinant inbred line (RIL) containing the insertion region were genotyped to classify individuals with and without the insertion. We also measured gene copy number which showed variation between parents and individuals of the populations. Increase copy number of the duplicate gene showed significant correlation with improved TSWV resistance. These results indicate the potential for improved TSWV resistance in future peanut cultivars.

Technical Abstract: Arachis hypogaea (cultivated peanut) is an important crop that can be highly susceptible to Tomato Spotted Wilt Virus (TSWV). Genetic resistance is desired to prevent major yield losses for growers. SSD6 and its progeny NC94022 have been introduced as resistance sources for breeding new varieties. Genetic evaluation of NC94022 previously reported a quantitative trait locus (QTL) for resistance on chromosome A01. Subsequently, an insertion region from NC94022 relative to the reference ‘Tifrunner’ was found from whole genome sequencing, and molecular markers were designed for marker-assisted selection. A duplicated glutamate receptor was identified within the insertion region as a potential candidate gene. Eight populations derived from crosses of eight unique parents with a single recombinant inbred line (RIL) containing the insertion region were genotyped to classify individuals with and without the insertion. Digital droplet PCR, used to assay candidate gene copy number, showed variation between parents and among individuals of the populations. Field evaluation over three generations revealed a significant increase in TSWV resistance when the insertion region was present. All populations showed improved resistance compared with susceptible varieties and their unique parents but few were as resistant as NC94022 or the RIL parent. Increased copy number of the duplicated gene showed significant correlation with improved TSWV resistance. These results indicate the potential for improved TSWV resistance from SSD6 but show that additional resistance loci need to be explored for further understanding of the genetic basis for this resistance.