A single amino acid residue substitution in BraA04g017190.3C, a histone methyltransferase, results in premature bolting in Chinese cabbage (Brassica rapa L. ssp. Pekinensis)

Abstract Background Flowering is an important inflection point in the transformation from vegetative to reproductive growth, and premature bolting severely decreases crop yield quality. Results In this study, a stable early-bolting mutant, ebm3 , was identified ethyl methanesulfonate (EMS)-mutagenized population of Chinese cabbage doubled haploid (DH) line ‘FT’. Compared with ‘FT’, showed early under natural cultivation autumn, curled leaves. Genetic analysis that phenotype controlled by single recessive nuclear gene. Modified MutMap sequencing, genotyping analyses allelism test provide strong evidence BrEBM3 ( BraA04g017190.3 C ), encoding histone methyltransferase CURLY LEAF (CLF), strongly candidate gene emb3 . A T base substitution 14th exon resulted amino acid change (S F) The mutation occurred SET domain (Suppressor protein-effect variegation 3–9, Enhancer-of-zeste, Trithorax), which catalyzes site- state-specific lysine methylation histones. Tissue-specific expression highly expressed flower bud. Promoter activity assay confirmed promoter active inflorescences. Subcellular localization revealed localized nucleus. Transcriptomic studies supported might repress H3K27me3 deposition activate AGAMOUS AG ) - like AGL loci, resulting flowering. Conclusions Our study EMS-induced mutant caused nonsynonymous CLF. These results improve our knowledge genetic genomic resources flowering, may be beneficial improvement cabbage.