title: Major Quantitative Trait Loci and Putative Candidate Genes for Powdery Mildew Resistance and Fruit-Related Traits Revealed by an Intraspecific Genetic Map for Watermelon (Citrullus lanatus var. lanatus).
abstract: An intraspecific genetic map for watermelon was constructed using an F2 population derived from 'Arka Manik' × 'TS34' and transcript sequence variants and quantitative trait loci (QTL) for resistance to powdery mildew (PMR), seed size (SS), and fruit shape (FS) were analyzed. The map consists of 14 linkage groups (LGs) defined by 174 cleaved amplified polymorphic sequences (CAPS), 2 derived-cleaved amplified polymorphic sequence markers, 20 sequence-characterized amplified regions, and 8 expressed sequence tag-simple sequence repeat markers spanning 1,404.3 cM, with a mean marker interval of 6.9 cM and an average of 14.6 markers per LG. Genetic inheritance and QTL analyses indicated that each of the PMR, SS, and FS traits is controlled by an incompletely dominant effect of major QTLs designated as pmr2.1, ss2.1, and fsi3.1, respectively. The pmr2.1, detected on chromosome 2 (Chr02), explained 80.0% of the phenotypic variation (LOD = 30.76). This QTL was flanked by two CAPS markers, wsb2-24 (4.00 cM) and wsb2-39 (13.97 cM). The ss2.1, located close to pmr2.1 and CAPS marker wsb2-13 (1.00 cM) on Chr02, explained 92.3% of the phenotypic variation (LOD = 68.78). The fsi3.1, detected on Chr03, explained 79.7% of the phenotypic variation (LOD = 31.37) and was flanked by two CAPS, wsb3-24 (1.91 cM) and wsb3-9 (7.00 cM). Candidate gene-based CAPS markers were developed from the disease resistance and fruit shape gene homologs located on Chr.02 and Chr03 and were mapped on the intraspecific map. Colocalization of these markers with the major QTLs indicated that watermelon orthologs of a nucleotide-binding site-leucine-rich repeat class gene containing an RPW8 domain and a member of SUN containing the IQ67 domain are candidate genes for pmr2.1 and fsi3.1, respectively. The results presented herein provide useful information for marker-assisted breeding and gene cloning for PMR and fruit-related traits.
authors.affiliation: Department of Horticultural Bioscience, Pusan National University, Miryang, Republic of Korea.
authors.forename: Kwang-Hwan
authors.initials: KH
authors.lastname: Kim
authors.affiliation: Department of Horticultural Bioscience, Pusan National University, Miryang, Republic of Korea.
authors.forename: Ji-Hyun
authors.initials: JH
authors.lastname: Hwang
authors.affiliation: Department of Horticultural Bioscience, Pusan National University, Miryang, Republic of Korea.
authors.forename: Dong-Yeup
authors.initials: DY
authors.lastname: Han
authors.affiliation: Department of Plant Science, Seoul National University, Seoul, Republic of Korea.|Department of Genetics, University of Georgia, Athens, Georgia, United States of America.
authors.forename: Minkyu
authors.initials: M
authors.lastname: Park
authors.affiliation: Department of Plant Science, Seoul National University, Seoul, Republic of Korea.
authors.forename: Seungill
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Plant Science, Seoul National University, Seoul, Republic of Korea.
authors.forename: Doil
authors.initials: D
authors.lastname: Choi
authors.affiliation: Partner Seed, Ansung, Republic of Korea.
authors.forename: Yongjae
authors.initials: Y
authors.lastname: Kim
authors.affiliation: Department of Integrative Plant Science, College of Biotechnology and Natural Resources, Chung-Ang University, Ansung, Republic of Korea.
authors.forename: Gung Pyo
authors.initials: GP
authors.lastname: Lee
authors.affiliation: Department of Plant Bioscience, Pusan National University, Miryang, Republic of Korea.
authors.forename: Sun-Tae
authors.initials: ST
authors.lastname: Kim
authors.affiliation: Department of Horticultural Bioscience, Pusan National University, Miryang, Republic of Korea.|Life and Industry Convergence Research Institute, Pusan National University, Miryang, Republic Korea.
authors.forename: Young-Hoon
authors.initials: YH
authors.lastname: Park
mesh_terms: D002874:Chromosome Mapping / Q000379:methods*; D032461:Chromosomes, Plant / Q000235:genetics; D029773:Citrullus / Q000235:genetics* / Q000254:growth & development; D060467:Disease Resistance / Q000235:genetics* / Q000276:immunology; D005638:Fruit / Q000235:genetics*; D008040:Genetic Linkage; D018745:Genome, Plant; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics*; D040641:Quantitative Trait Loci
chemical_list: D010940:Plant Proteins