Production of Red Flower Rapeseed by Ectopic Expression of OvPAP2 Identified in Brassica napus-Orychophragmus violaceus Addition Line by Comparative Transcriptome Analysis

Oilseed rape is both an important oleaginous crop and agriculture sightseeing crop whereas has relatively scanty flower color. As natural ?avonoids, Anthocyanin are responsible for the attractive red, purple, and blue colors of various tissues in higher plants, especially for the ornamental plants flower. One Brassica napus-Orychophragmus violaceus disomic addition line (M4) obtained previously exhibits red petals whichresult from anthocyanin biosynthesis. Transcriptome analysis of M4, B. napus (H3), natural individuals of O. violaceus with purple petals (OvP) and white petals (OvW) revealed that most of structural genes for the anthocyanin synthesis were up-regulated in both M4 and OvP, especially key gene ANS in the last step. Reads assembling and sequence alignment showed that the regulatory DEG PAP2 in M4 was from the transcript of O. violaceus. OvPAP2 was transformed into Arabidopsis thaliana and B. napus driven by the CaMV35S promoter and the rape petal-specific prompter XY355. Transgenic A. thaliana plants showed different levels of purple pigments in most of the organs, including the petals, and transgenic B. napus flowers exhibited restricted accumulation of anthocyanins in stamens when driven by CaMV35S promoter, but generated both red petals and anthers driven by the XY355 promoter. These results provided a platform for expounding the anthocyanin biosynthesis pathway in B. napus petals and give a successful case for flower color modification of the agriculture sightseeing rape. Overall design: The petals on half-open flowers were collected in liquid nitrogen from four samples:The disomic addition line with red petals (designated as M4), donor B. napus cv. Huashuang 3 (designated as H3), the wild type O. violaceus with purple petals (designated as OvP) and it's natural mutant with white petals (designated as OvW) , respectively, and kept at -80°C. Total RNA from the four samples were extracted and sequencing was performed using Illumina HiSeq 2000.

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