Rapid identification of the purple stem (Ps) gene of Chinese kale (Brassica oleracea var. alboglabra) in a segregation distortion population by bulked segregant analysis and RNA sequencing
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Abundant anthocyanins accumulate in many flowers, leaves, fruits, as well as stems. In this study, an F2 segregating population derived from a cross between Chinese kale with a purple stem and kale with a green stem was used to decipher the genetic basis for the stem color. Bulked segregant analysis in combination with RNA sequencing (BSR-seq) was used to genetically map the causal gene for the purple stem (Ps), and the allele frequency difference between the two pools showed a single peak on chromosome C09. Ps was fine-mapped to the 0.32 cM interval with 406 kb sequences. A gene-encoding dihydroflavonol 4-reductase (DFR), an enzyme in the anthocyanin biosynthesis pathway, was differentially expressed between the two pools, and was identified as the candidate gene for the purple stem in Chinese kale. Sequence analysis revealed that 1 bp was inserted in the coding sequence of exon 2 of the BoDRF gene in green kale, causing frameshift and loss of function. The expression level of the BoDFR gene was significantly lower than the Chinese kale cultivar with a purple stem. The genetic results of the Ps gene will be useful for future development of purple vegetables.
KeywordsChinese kale Anthocyanin BSR-seq Genetic mapping Dihydroflavonol 4-reductase
C.Y. designed the experiment. Q.T. and M.T. finished the major experiments. G.A. planted the population, detected the phenotypes and extracted DNA. W.Z. analyzed the BSR-seq. C.Y. wrote the manuscript, with help from J.C.
This work was supported by the Fundamental Research Funds for the Central Universities [2662015PY084] and [2014PY031] and the National Natural Science Foundation of China  and .
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Competing financial interests
The authors declare no competing financial interests.
- Gould KS 2004 Nature’s Swiss army knife: the diverse protective roles of anthocyanins in leaves. J Biomed Biotechnol 2004:314–20Google Scholar
- Michelmore RW, Paran I, Kesseli RV (1991) Identification of markers linked to disease-resistance genes by bulked segregant analysis: a rapid method to detect markers in specific genomic regions by using segregating populations. Proc Natl Acad Sci U S A 88:9828–9832CrossRefPubMedPubMedCentralGoogle Scholar
- Neill SO, Gould KS (2003) Anthocyanins in leaves: light attenuators or antioxidants? Functional Plant Biology 30 (8):865Google Scholar
- Sun B, Fang L, Liu N et al (2011) Studies on main nutritional components of Chinese Kale among different organs. Acta Horticultrae Sinica 3:021Google Scholar
- Van Ooijen, J. JoinMap 4 (2006) Software for the Calculation of Genetic Linkage Maps in Experimental Populations (Kyazma, Wageningen, The NetherlandsGoogle Scholar