Genotyping-by-Sequencing-Based Genome-Wide Association Studies of Fusarium Wilt Resistance in Radishes (Raphanus sativus L.).

O New Lee,Han Yong Park,Hyunjin Koo,Jae Woong Yu

doi:10.3390/genes12060858

Abstract

Fusarium wilt (FW) is a fungal disease that causes severe yield losses in radish production. The most effective method to control the FW is the development and use of resistant varieties in cultivation. The identification of marker loci linked to FW resistance are expected to facilitate the breeding of disease-resistant radishes. In the present study, we applied an integrated framework of genome-wide association studies (GWAS) using genotyping-by-sequencing (GBS) to identify FW resistance loci among a panel of 225 radish accessions, including 58 elite breeding lines. Phenotyping was conducted by manual inoculation of seedlings with the FW pathogen, and scoring for the disease index was conducted three weeks after inoculation during two constitutive years. The GWAS analysis identified 44 single nucleotide polymorphisms (SNPs) and twenty putative candidate genes that were significantly associated with FW resistance. In addition, a total of four QTLs were identified from F2 population derived from a FW resistant line and a susceptible line, one of which was co-located with the SNPs on chromosome 7, detected in GWAS study. These markers will be valuable for molecular breeding programs and marker-assisted selection to develop FW resistant varieties of R. sativus.

Highlights

Radishes (R. sativus L., 2n = 18) belong to the Brassicaceae family, and are an economically important crop that is globally utilized
We evaluated Fusarium wilt (FW) resistance to F. oxysporum f. sp. raphani in 225 R. sativus accessions in 2015 and 2016
Genome-wide association study has been used to detect putative functional markers and candidate genes related to complex traits of various plant species [25,49,50]

Summary

Introduction

Radishes (R. sativus L., 2n = 18) belong to the Brassicaceae family, and are an economically important crop that is globally utilized. The swollen taproot, young leaves, fresh sprouts, and immature siliques are eaten as vegetables, and are consumed raw, pickled, dried, and cooked [1]. All radish types are cultivated as animal fodder, and oil radishes are used as a source of seed oil. Radish production is estimated at approximately seven million tons/year for global production, and it represents about 2% of total worldwide vegetable production [4]. Radishes are an important vegetable in Asia, especially in China, Japan, and Korea, and the estimated radish production areas in the three countries are 1.2 million, 33,000, and 20,000 hectares, respectively [5,6]

Methods

Results

Conclusion