Identification and Characterization of Anthocyanin Biosynthesis-Related Genes in Kohlrabi.

Kohlrabi (<italic>Brassica oleracea</italic> var<italic>. gongylodes</italic> L.) is an important vegetable of the <italic>Brassicaceae</italic> family. The main edible part of kohlrabi is the swollen stem. The purple cultivars make anthocyanin mainly in the peel of the swollen stem, while in the leaf, it is limited to the midrib, but green cultivars do not. Anthocyanins are advantageous for both plants as well as humans. Two anthocyanin compounds were detected by high pressure liquid chromatography (HPLC) only in the peel of the purple kohlrabi cultivar. Three MYBs, three bHLHs, and one WD40 TF were identified as the candidate regulatory genes in kohlrabi. There was an abundance of transcript levels for the late biosynthetic genes more specifically for <italic>BoF3′H</italic>, <italic>BoDFR</italic>, <italic>BoLDOX</italic>, and <italic>BoGST</italic> in the purple peel while scarcely detectable in other tissues for both cultivars. The expression of <italic>BoPAP2</italic> and <italic>BoTT8</italic> was higher in the peel of the purple cultivar than the green cultivar. The expression of <italic>BoMYBL2.2</italic> orthologue of <italic>Arabidopsis MYBL2</italic>, a negative regulator of anthocyanins, was dramatically decreased in the purple peel. The expression of <italic>BoACO1</italic>, a key gene for ethylene biosynthesis, and <italic>BoNCED3</italic>, an important gene of the ABA pathway, was down- and upregulated, respectively, in the peel of purple kohlrabi. [ABSTRACT FROM AUTHOR]