Anthocyanins identification and transcriptional regulation of anthocyanin biosynthesis in purple Brassica napus.

key messageThe main anthocyanin components were identified, and the transcriptional regulation pattern of anthocyanin related genes in leaves and stem bark was elucidated in a purple B. napus. Brassica napus is one of the most important oil crops planted worldwide, and developing varieties of dual-purpose for oil and vegetable is beneficial to improve economic benefits. Anthocyanins are a class of secondary metabolites that not only make plants present beautiful colors, but have a variety of important physiological functions and biological activities. Therefore, increasing the accumulation of anthocyanin in vegetative organs can improve vegetable value of rapeseed. However, anthocyanin enriched varieties in vegetative organs are rare, and there are few studies on category identification and accumulation mechanism of anthocyanin, which limits the utilization of anthocyanins in B. napus. In this study, 157 anthocyanin biosynthesis related genes (ABGs) were identified in B. napus genome by homology comparison and collinearity analysis of genes related to anthocyanin synthesis and regulation in Arabidopsis. Moreover, five anthocyanins were identified in the stem bark and leaves of the purple B. napus PR01 by high performance liquid chromatography-mass spectrometry (HPLC-MS), and the expression characteristics of ABGs in the leaves and stem bark of PR01 were analyzed and compared with the green cultivar ZS11 by RNA-Seq. Combining further weighted gene co-expression network analysis (WGCNA), the up-regulation of transcript factors BnaA07. PAP2 and BnaC06. PAP2 were identified as the key to the up-regulation of most of anthocyanin synthesis genes that promoted anthocyanin accumulation in PR01. This study is helpful to understand the transcriptional regulation of anthocyanin biosynthesis in B. napus and provides the theoretical basis for breeding novel varieties of dual-purpose for oil and vegetable.