A Major and Stable QTL for Bacterial Wilt Resistance on Chromosome B02 Identified Using a High-Density SNP-Based Genetic Linkage Map in Cultivated Peanut Yuanza 9102 Derived Population.

Yuning Chen,Weigang Chen,Yong Lei,Jinxiong Shen,Li Huang,Xiaoping Ren,Boshou Liao,Xiaojing Zhou,Nian Liu,Liying Yan,Lifang Wang,Huaiyong Luo,Huifang Jiang

doi:10.3389/fgene.2018.00652

Abstract

Bacterial wilt (BW) is one of the important diseases limiting the production of peanut (Arachis hypogaea L.) worldwide. The sufficient precise information on the quantitative trait loci (QTL) for BW resistance is essential for facilitating gene mining and applying in molecular breeding. Cultivar Yuanza 9102 is BW resistant, bred from wide cross between cultivated peanut Baisha 1016 and a wild diploid peanut species A. chacoense with BW resistance. In this study, we aim to map the major QTLs related to BW-resistance in Yuanza 9102. A high density SNP-based genetic linkage map was constructed through double-digest restriction-site-associated DNA sequencing (ddRADseq) technique based on Yuanza 9102 derived recombinant inbred lines (RILs) population. The map contained 2,187 SNP markers distributed on 20 linkage groups (LGs) spanning 1566.10 cM, and showed good synteny with AA genome from A. duranensis and BB genome from A. ipaensis. Phenotypic frequencies of BW resistance among RIL population showed two-peak distribution in four environments. Four QTLs explaining 5.49 to 23.22% phenotypic variance were identified to be all located on chromosome B02. The major QTL, qBWB02.1 (12.17–23.33% phenotypic variation explained), was detected in three environments showing consistent and stable expression. Furthermore, there was positive additive effect among these major and minor QTLs. The major QTL region was mapped to a region covering 2.3 Mb of the pseudomolecule B02 of A. ipaensis which resides in 21 nucleotide-binding site -leucine-rich repeat (NBS-LRR) encoding genes. The result of the major stable QTL (qBWB02.1) not only offers good foundation for discovery of BW resistant gene but also provide opportunity for deployment of the QTL in marker-assisted breeding in peanut.

Highlights

Cultivated peanut (Arachis hypogaea L.) is an important oilseed crop in the world (Bertioli et al, 2016; Varshney et al, 2017)
A recombinant inbred lines (RILs) population including 188 F7 lines derived from the cross between Yuanza 9102 and Xuzhou 68-4 was used in this study
161.39 million reads came from the parents, and ∼3558.38 million reads came from the libraries for the 188 RIL lines

Summary

Introduction

Cultivated peanut (Arachis hypogaea L.) is an important oilseed crop in the world (Bertioli et al, 2016; Varshney et al, 2017). The bacterial wilt (BW) caused by Ralstonia solanacearum is the most important soil-borne bacterial disease in peanut, especially destructive in China. It results in yield loss more than 50% even extinction (Wicker et al, 2007; Yu et al, 2011) This disease is seriously harmful to tomato, eggplant, chili, potato, tobacco, and other crops (Cao et al, 2009; Liao et al, 2010; Prasath et al, 2011; Narusaka et al, 2014; Xiao et al, 2015). The most effective and economic measure is to breed and plant BW resistant cultivar (Lyu et al, 2010; Sunkara et al, 2014; Bhatnagar-Mathur et al, 2015)

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