QTL Mapping and Candidate Gene Identification of Swollen Root Formation in Turnip

• Published in: International journal of molecular sciences 2021-01, Vol.22 (2), p.653
• Main Authors: Wu, Yudi, Zhang, Shifan, Zhang, Hui, Li, Fei, Li, Guoliang, Fan, Chuchuan, Sun, Rifei, Zhang, Shujiang
• Format: Article
• Language: English
• Subjects: Agronomy; Brassica napus - anatomy & histology; Brassica napus - genetics; Brassica napus - growth & development; Brassica rapa; candidate gene; Cell adhesion; Cell division; Chinese cabbage; Chromosome Mapping; Chromosomes; Crops; Deoxyribonucleic acid; DNA; Gene mapping; Genes; Genes, Plant; Genetic Linkage; Genetic Markers; Genomes; Genomics; Histocytochemistry; Homology; Mapping; MicroRNAs; Morphology; Phenotype; Phenotypic variations; Physiology; Plant Roots - anatomy & histology; Plant Roots - genetics; Plant Roots - growth & development; Populations; QTL; Quantitative Trait Loci; Quantitative Trait, Heritable; Sucrose; swollen root; turnip; Turnips
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms22020653

The swollen root is an important agronomic trait and is a determinant of yield for turnips, which are cultivated as both vegetables and fodder. However, the genetic mechanism of swollen root formation is poorly understood. In this study, we analyzed the F and BC P populations derived from a cross between "10601" (European turnip with swollen root, ssp. , AA, 2n = 2× = 20) and "10603" (Chinese cabbage with normal root, ssp. , AA, 2n = 2× = 20), and suggested that the swollen root is a quantitative trait. Two major quantitative trait loci (QTLs), (Fleshy root 1.1) and (Fleshy root 7.1), were identified by QTL-seq analysis and further confirmed by QTL mapping in F and BC P populations. The QTL with a likelihood of odd (LOD) of 7.01 explained 17.2% of the total phenotypic variations for root diameter and the QTL explained 23.0% (LOD = 9.38) and 31.0% (LOD = 13.27) of the total phenotypic variations in root diameter and root weight, respectively. After a recombinant screening, the major QTL was further narrowed down to a 220 kb region containing 47 putative genes. A candidate gene, , which is a homolog of that plays an essential role in cell adhesion and disorganized tumor-like formation in , was identified in this region. In addition, expression and parental allele analysis supported that was a possible candidate gene of QTL for swollen root formation in turnip. Our research may provide new insight into the molecular mechanism of swollen root formation in root crops.