Characterization of the complete chloroplast genome of purple flowering stalk (Brassica campestris var. purpuraria) and comparisons with related species

Purple flowering stalk (Brassica campestris var. purpuraria) is an important vegetable and is widely distributed in the region of the Yangtze River. In the present study, we reported the chloroplast genome of B. campestris var. purpuraria and compared it with previously reported chloroplast genomes in the Brassicaceae family. The whole chloroplast genome length of B. campestris var. purpuraria was 153,483 bp with 36.36% GC, including a large single-copy region (LSC, 83,282 bp), a small single-copy region (SSC, 17,775 bp), and two inverted repeat regions (IRa and IRb, both are 26,213 bp). A total of 132 genes were annotated, containing 87 protein-coding genes, 37 transfer RNA genes, and 8 ribosomal RNA genes. The genome contained 37 repeat sequences, and 315 simple sequence repeat (SSR) sites and the most preferred codon was AUG. Six genes of ycf1, matK, rpl22, trnF-GAA, ccsA, and rps16 exhibited high nucleotide diversity (Pi) values. Phylogenetic analysis indicated that the chloroplast of B. campestris var. purpuraria was mostly related to B. rapa. The results would further be beneficial for molecular identification, phylogenetic analysis and biological research of Brassica species.