Anthocyanins confer the wide range of colors for plants and also play beneficial health roles as potentially protective factors against heart disease and cancer. Brassica juncea is cultivated as an edible oil resource and vegetable crop worldwide, thus elucidating the anthocyanin biosynthetic pathway would be helpful to improve the nutritional quality of Brassica juncea through the breeding and cultivating of high anthocyanin content varieties. Herein, 129 genes in B. juncea were identified as orthologs of 41 anthocyanin biosynthetic genes (ABGs) in Arabidopsis thaliana by comparative genomic analyses. The B. juncea ABGs have expanded by whole genome triplication and subsequent allopolyploidizatoin, but lost mainly during the whole genome triplication between B. rapa/B. nigra and A. thaliana, rather than the allopolyploidization process between B. juncea and B. rapa/B. nigra, leading to different copy numbers retention of A. thaliana homologous genes. Although the overall expansion levels ABGs were similar to the whole genome, more negative regulatory genes were retained in the anthocyanin biosynthesis regulatory system. Transcriptional analysis of B. juncea with different anthocyanin accumulation showed that BjDFR, BjTT19, BjTT8 are significantly up-regulated in plants with purple leaves as compared with green leaves. The overexpression of BjTT8 and these target genes which were involved in late anthocyanin biosynthesis and transport might account for increasing levels of anthocyanin accumulation in purple leaves. Our results could promote the understanding of the genetic mechanism of anthocyanin biosynthesis in B. juncea.

花青素为植物赋予了广泛的颜色，并且还具有有益的健康作用，可作为预防心脏病和癌症的潜在保护因子。芥菜在世界范围内作为食用油和蔬菜作物而被种植，因此阐明花青素的生物合成途径将有助于通过选育高花青素含量的品种来改善芥菜的营养品质。在这里，通过比较基因组分析，在芥菜中的129个基因被鉴定为拟南芥中41个花色苷生物合成基因（ABG）的直系同源物。该芥菜ABGs通过全基因组三倍和随后的同聚多倍体化而扩大，但主要在B. rapa / B之间的全基因组三倍期间丢失。黑质和拟南芥，而不是之间的异源多倍体过程芥菜和芜菁/ B。黑质，导致拟南芥同源基因具有不同的拷贝数保留。尽管ABG的总体扩增水平与整个基因组相似，但更多的负调节基因保留在花色苷生物合成调节系统中。对具有不同花色苷积累的芥菜芽孢杆菌的转录分析表明，BjDFR，BjTT19，BjTT8与绿色的叶子相比，紫色叶子的植物中的蛋白显着上调。BjTT8和这些靶基因的过表达与后期花青素的生物合成和转运有关，可能解释了紫色叶中花青素积累水平的提高。我们的结果可以促进对芥菜花色苷生物合成遗传机制的理解。