Molecular cloning and characterization of an anti-bolting related gene (BrpFLC) from Brassica rapa ssp. Pekinensis

Bolting reduces the commercial value of Chinese cabbage, so inhibiting Chinese cabbage from bolting is important. Flowering locus C (FLC), a repressor of flowering, encodes a MADS-domain transcription factor in Arabidopsis thaliana. Here we report on the cloning and characterization of a FLC homologous gene from Chinese cabbage (designated as BrpFLC, GenBank accession number: AY364013) using RACE-PCR. The full-length cDNA of BrpFLC was 851 base pair (bp) and contained a 591 bp open reading frame (ORF) encoding a protein with 197 amino acid residues. The BrpFLC gene had a high degree of similarity to Brassica napus MADS-box protein mRNA (AY036890) and Brassica rapa cultivar samjin flowering locus C (FLC) mRNA (AY273162). Southern blot analysis indicated that the FLC gene belonged to a multi-gene family when the coding sequence of BrpFLC was used as a probe, and there was a single copy when a 3′ UTR region was used as a probe. Northern blot analysis using the 3′ UTR of BrpFLC as the probe revealed that the transcript level of BrpFLC of different anti-bolting Chinese cabbage cultivars was reduced by vernalization at different degrees, and the BrpFLC transcript levels of anti-bolting cultivars remained higher than those of easy bolting cultivars after vernalization, implying that the degree of vernalization sensitivity of the BrpFLC gene was related to the level of bolting of Chinese cabbage.