title: Identification of Flowering-Related Genes Responsible for Differences in Bolting Time between Two Radish Inbred Lines.
abstract: Late bolting after cold exposure is an economically important characteristic of radish (Raphanus sativusL.), an important Brassicaceae root vegetable crop. However, little information is available regarding the genes and pathways that govern flowering time in this species. We performed high-throughput RNA sequencing analysis to elucidate the molecular mechanisms that determine the differences in flowering times between two radish lines, NH-JS1 (late bolting) and NH-JS2 (early bolting). In total, 71,188 unigenes were identified by reference-guided assembly, of which 309, 788, and 980 genes were differentially expressed between the two inbred lines after 0, 15, and 35 days of vernalization, respectively. Among these genes, 218 homologs ofArabidopsisflowering-time (Ft) genes were identified in the radish, and 49 of these genes were differentially expressed between the two radish lines in the presence or absence of vernalization treatment. Most of the Ft genes up-regulated in NH-JS1 vs. NH-JS2 were repressors of flowering, such asRsFLC, consistent with the late-bolting phenotype of NH-JS1. Although, the functions of genes down-regulated in NH-JS1 were less consistent with late-bolting characteristics than the up-regulated Ft genes, several Ft enhancer genes, includingRsSOC1, a key floral integrator, showed an appropriate expression to the late-bolting phenotype. In addition, the patterns of gene expression related to the vernalization pathway closely corresponded with the different bolting times of the two inbred lines. These results suggest that the vernalization pathway is conserved between radish andArabidopsis.
authors.affiliation: Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology Daejeon, Korea.
authors.forename: Won Yong
authors.initials: WY
authors.lastname: Jung
authors.affiliation: Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology Daejeon, Korea.
authors.forename: Hyun Ji
authors.initials: HJ
authors.lastname: Park
authors.affiliation: Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and BiotechnologyDaejeon, Korea; Biosystems and Bioengineering Program, University of Science and TechnologyDaejeon, South Korea.
authors.forename: Areum
authors.initials: A
authors.lastname: Lee
authors.affiliation: Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology Daejeon, Korea.
authors.forename: Sang Sook
authors.initials: SS
authors.lastname: Lee
authors.affiliation: Department of Biotechnology, NongHyup Seed Anseong, South Korea.
authors.forename: Youn-Sung
authors.initials: YS
authors.lastname: Kim
authors.affiliation: Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and BiotechnologyDaejeon, Korea; Biosystems and Bioengineering Program, University of Science and TechnologyDaejeon, South Korea.
authors.forename: Hye Sun
authors.initials: HS
authors.lastname: Cho
keywords: RNA sequencing; flowering time-related gene; late bolting; radish (Raphanus sativus L.); vernalization