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ARS Home » Southeast Area » Dawson, Georgia » National Peanut Research Laboratory » Research » Publications at this Location » Publication #345870

Research Project: Developing Strategies to Identify Useful Genes in Peanut and Breeding High Yielding Peanut Varieties and Germplasm

Location: National Peanut Research Laboratory

Title: Refining a major QTL controlling spotted wilt disease resistance in cultivated peanut (Arachis hypogaea L.)and evaluating its contribution to the resistance variations in peanut germplasm

Author
item Zhao, Zifan - University Of Florida
item Tseng, Yu-chien - University Of Florida
item Peng, Ze - University Of Florida
item Lopez, Yolanda - University Of Florida
item Chen, Charles - Auburn University
item Tillman, Barry - University Of Florida
item Dang, Phat
item Wang, Jianping - University Of Florida

Submitted to: BioMed Central (BMC) Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/9/2018
Publication Date: 3/23/2018
Citation: Zhao, Z., Tseng, Y., Peng, Z., Lopez, Y., Chen, C.Y., Tillman, B.L., Dang, P.M., Wang, J. 2018. Refining a major QTL controlling spotted wilt disease resistance in cultivated peanut (Arachis hypogaea L.)and evaluating its contribution to the resistance variations in peanut germplasm. BioMed Central (BMC) Genetics. 19:17.

Interpretive Summary: Spotted wilt, caused by tomato spotted wilt virus (TSWV), has been one of major diseases in cultivated peanut grown in the southeastern United States (US) since 1990. Infected plants can be stunted and defoliate spotted leaves, resulting in significant yield loss. Development of resistant varieties is a sustainable strategy to combat this disease. Previously a major quantitative trait locus (QTL) controlling spotted wilt disease resistance was identified to reside on a genetic region of chromosome A01 in peanut utilizing a second-generation segregating population. The current study focuses on refining this major region and surveys its prevalence in the United States peanut mini-core germplasm collection. Two simple sequence repeat (SSR) type genetic markers were associated with this major QTL utilizing a fifth-generation segregating population. Based on visual evaluation in the field, a total of 194 susceptible sixth-generation individuals were selected and progressed to seventh-generation for trait identification. Utilizing nine SSR markers and two insertion/deletion (indel) type genetic markers, the major QTL location was refined to a 0.8 Mega base (Mb) region between two indel markers. To test whether this QTL exists in United States peanut mini-core germplasm collection, two flanking SSR markers were used to evaluate genetic variations of the 107 mini-core germplasm accessions. No statistically significant association was observed at the major QTL region between segregating population and the mini-core germplasm collection. In conclusion, a major QTL related to spotted wilt disease resistance in peanut was narrowed to a 0.8 Mb region on A01 chromosome, which was likely to be unique and didn’t contribute to spotted wilt disease resistance in the US peanut mini-core germplasm. Identification of a more precise TSWV resistance gene region will enable breeders to developed improved peanut varieties utilizing marker assisted plant selection.

Technical Abstract: Spotted wilt, caused by tomato spotted wilt virus (TSWV), has been one of major diseases in cultivated peanut grown in the southeastern United States (US) since 1990. Previously a major quantitative trait locus (QTL) controlling spotted wilt disease resistance was mapped to an interval of 2.55 centimorgan (cM) genetic distance corresponding to a physical distance of 14.4 megabase (Mb) on chromosome A01 of peanut by using a segregating filial (F)2 population. The current study focuses on refining this major QTL region and surveys the prevalence of this QTL in the US peanut mini-core germplasm. Two simple sequence repeat (SSR) markers associated with the major QTL were used to genotype F¬5 individuals, and 25 heterozygous individuals were selected and developed into an F6 segregating population. Based on visual evaluation in the field, a total of 194 susceptible F6 individuals were selected and planted into F7 generation for phenotyping. Nine SSR markers were used to genotype the 194 F6 individual, and QTL analysis revealed that a confidence interval of 15.2 Mb regions had the QTL with 22.8% phenotypic variation explained (PVE). This QTL interval was further genotyped using the Amplicon-seq method. A total of 81 non-redundant single nucleotide polymorphism (SNP) and eight InDel markers were detected. No recombinant was detected among the F6 individuals. Two InDel markers were mapped into the linkage group and helped to refine the confidence interval of this QTL into a 0.8 Mb region. To test whether this QTL exists in US peanut mini-core germplasm, two flanking SSR markers were used to genotype 107 mini-core germplasm accessions. No statistically significant association was observed between the genotype at the QTL region and spotted wilt resistance in the mini-core germplasm, which indicated that the QTL detected in this study was unique and didn’t contribute to the resistance variance in the US peanut mini-core germplasm. A major QTL related to spotted wilt disease resistance in peanut was refined to a 0.8 Mb region on A01 chromosome, which was likely to be unique and didn’t contribute to spotted wilt disease resistance in the US peanut mini-core germplasm.