QTL Mapping and Candidate Gene Identification of Swollen Root Formation in Turnip
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<sub>2</sub> and BC<sub>1&l...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2021-01-01
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| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/22/2/653 |
| Summary: | 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<sub>2</sub> and BC<sub>1</sub>P<sub>2</sub> populations derived from a cross between “10601” (European turnip with swollen root, <i>Brassica rapa</i> ssp. <i>rapifera</i>, AA, 2n = 2× = 20) and “10603” (Chinese cabbage with normal root, <i>Brassica rapa</i> ssp. <i>pekinensis</i>, AA, 2n = 2× = 20), and suggested that the swollen root is a quantitative trait. Two major quantitative trait loci (QTLs), <i>FR1.1</i> (Fleshy root 1.1) and <i>FR7.1</i> (Fleshy root 7.1), were identified by QTL-seq analysis and further confirmed by QTL mapping in F<sub>2</sub> and BC<sub>1</sub>P<sub>2</sub> populations. The QTL <i>FR1.1</i> with a likelihood of odd (LOD) of 7.01 explained 17.2% of the total phenotypic variations for root diameter and the QTL <i>FR7.1</i> 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 <i>FR7.1</i> was further narrowed down to a 220 kb region containing 47 putative genes. A candidate gene, <i>Bra003652</i>, which is a homolog of <i>AT1G78240</i> that plays an essential role in cell adhesion and disorganized tumor-like formation in <i>Arabidopsis thaliana</i>, was identified in this region. In addition, expression and parental allele analysis supported that <i>Bra003652</i> was a possible candidate gene of QTL <i>FR7.1</i> for swollen root formation in turnip. Our research may provide new insight into the molecular mechanism of swollen root formation in root crops. |
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| ISSN: | 1661-6596 1422-0067 |