title: Uncovering novel loci for mesocotyl elongation and shoot length in indica rice through genome-wide association mapping.
abstract: Totally, 23 loci were detected, and 383 candidate genes were identified, and four of these candidate genes, Os01g0392100, Os04g0630000, Os01g0904700 and Os07g0615000, were regarded as promising targets. Direct-seeding cultivation is becoming popular in rice (Oryza sativa L.)-planting countries because it is labor- and time-efficient. However, low seedling establishment and slow seedling emergence have restricted the application and popularity of the technique. Mesocotyl elongation and shoot length are two important traits that can enhance rice seedling emergence. A single nucleotide polymorphism (SNP) is a genome sequence variation caused by a single base within a population, and SNPs evenly distributed throughout the genomes of plant species. In this study, a genome-wide association study (GWAS), based on 4136 SNPs, was performed using a compressed mixed linear model that accounted for population structure and relative kinship to detect novel loci for the two traits. Totally, 23 loci were identified, including five loci located known QTLs region. For the mesocotyl elongation, 17 major loci were identified, explaining ~19.31 % of the phenotypic variation. For the shoot length, six major loci were detected, explaining ~ 39.79 % of the phenotypic variation. In total, 383 candidate genes were included in a 200-kb genomic region (± 100 kb of each locus). Additionally, 32 SNPs were identified in 30 candidate genes. Relative expression level analyses indicated that four candidate genes containing SNP variations, Os01g0392100, Os04g0630000, Os01g0904700 and Os07g0615000, represented promising targets. Finally, eight elite accessions with long mesocotyl and shoot lengths were chosen as breeding donors for further rice direct-seeding variety modifications.
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China. luqing2016@126.com.
authors.forename: Qing
authors.initials: Q
authors.lastname: Lu
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China. theJust@126.com.
authors.forename: Mengchen
authors.initials: M
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China. xiaojunwords@126.com.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Niu
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China. wangcaihong@caas.com.
authors.forename: Caihong
authors.initials: C
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China. xuqun37@hotmail.com.
authors.forename: Qun
authors.initials: Q
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China. fy_555500@163.com.
authors.forename: Yue
authors.initials: Y
authors.lastname: Feng
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China. wangshan7628@163.com.
authors.forename: Shan
authors.initials: S
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China. yxp641110@163.com.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Yuan
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China. yuhy540@163.com.
authors.forename: Hanyong
authors.initials: H
authors.lastname: Yu
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China. cnwangyp@126.com.
authors.forename: Yiping
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China. weixinghua@caas.cn.
authors.forename: Xinghua
authors.initials: X
authors.lastname: Wei
mesh_terms: D001947:Breeding; D002874:Chromosome Mapping; D055106:Genome-Wide Association Study; D012275:Oryza / Q000235:genetics* / Q000254:growth & development; D010641:Phenotype; D018520:Plant Shoots / Q000235:genetics / Q000254:growth & development; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci; D036226:Seedlings / Q000235:genetics / Q000254:growth & development; D017422:Sequence Analysis, DNA
keywords: Direct-seeding; Genome-wide association study; Mesocotyl elongation; Rice (Oryza sativa L.); Shoot length