title: QTL mapping for bacterial wilt resistance in peanut (Arachis hypogaeaL.).
abstract: Bacterial wilt (BW) caused byRalstonia solanacearumis a serious, global, disease of peanut (Arachis hypogaeaL.), but it is especially destructive in China. Identification of DNA markers linked to the resistance to this disease will help peanut breeders efficiently develop resistant cultivars through molecular breeding. A F2population, from a cross between disease-resistant and disease-susceptible cultivars, was used to detect quantitative trait loci (QTL) associated with the resistance to this disease in the cultivated peanut. Genome-wide SNPs were identified from restriction-site-associated DNA sequencing tags using next-generation DNA sequencing technology. SNPs linked to disease resistance were determined in two bulks of 30 resistant and 30 susceptible plants along with two parental plants using bulk segregant analysis. Polymorphic SSR and SNP markers were utilized for construction of a linkage map and for performing the QTL analysis, and a moderately dense linkage map was constructed in the F2population. Two QTL (qBW-1 andqBW-2) detected for resistance to BW disease were located in the linkage groups LG1 and LG10 and account for 21 and 12 % of the bacterial wilt phenotypic variance. To confirm these QTL, the F8RIL population with 223 plants was utilized for genotyping and phenotyping plants by year and location as compared to the F2population. The QTLqBW-1 was consistent in the location of LG1 in the F8population though the QTLqBW-2 could not be clarified due to fewer markers used and mapped in LG10. The QTLqBW-1, including four linked SNP markers and one SSR marker within 14.4-cM interval in the F8, was closely related to a disease resistance gene homolog and was considered as a candidate gene for resistance to BW. QTL identified in this study would be useful to conduct marker-assisted selection and may permit cloning of resistance genes. Our study shows that bulk segregant analysis of genome-wide SNPs is a useful approach to expedite the identification of genetic markers linked to disease resistance traits in the allotetraploidy species peanut.
authors: Tuskegee University, Tuskegee, AL 36088 USA.
authors: Yongli
authors: Y
authors: Zhao
authors: Key Laboratory of Crop Molecular and Cell Biology, Fujian Agriculture and Forestry University, Fuzhou, China.
authors: Chong
authors: C
authors: Zhang
authors: Key Laboratory of Crop Molecular and Cell Biology, Fujian Agriculture and Forestry University, Fuzhou, China.
authors: Hua
authors: H
authors: Chen
authors: Shandong Peanut Research Institute, Qingdao, China.
authors: Mei
authors: M
authors: Yuan
authors: Floragenex Inc., Portland, OR 97239 USA.
authors: Rick
authors: R
authors: Nipper
authors: Tuskegee University, Tuskegee, AL 36088 USA.
authors: C S
authors: CS
authors: Prakash
authors: Key Laboratory of Crop Molecular and Cell Biology, Fujian Agriculture and Forestry University, Fuzhou, China.
authors: Weijian
authors: W
authors: Zhuang
authors: Tuskegee University, Tuskegee, AL 36088 USA.
authors: Guohao
authors: G
authors: He
keywords: BSA; Bacterial wilt; Peanut; QTL analysis; RAD sequencing; Resistance gene homolog; SNP; SSR