Co-expression of basic helix-loop-helix protein (bHLH) and transcriptional activator-Myb genes induced anthocyanin biosynthesis in hairy root culture of Nicotiana tabacum L and Ipomea tricolor

Anthocyanins are important plant secondary metabolites with chromone that undergo hydroxylation, methylation, and glycosylation. Some special anthocyanins only reside in special tissues of special plants. The easy way to produce them should aid in utilizing these complex compounds and understanding the molecular mechanism of its biosynthesis. In the presence study, both bHLH and MYB genes were successfully transformed into hairy root of tobacco 'Samsun' and morning glory 'heavenly blue' using the Agrobacterium rhizogenesis-mediated technique. The transgenic hairy roots were red in both plants, while the wild-type hairy roots were white. The real-time quantitative reverse transcription PCR (qRT-PCR) analysis discovered that the transcript levels of the structural genes related to anthocyanin biosynthesis in the transformed hairy roots of tobacco were 50-500 times higher than the wild type. The red hairy root of 'Samsun' contained 1.46% total anthocyanins. The anthocyanin components in the hairy roots of 'Samsun' were similar to those in the flowers, with the cyanidin linked to a glucose and a ferulic acid. Transformed hairy roots of morning glory were found to contain ten types of anthocyanins that differ than in flower, and anthocyanins present in flower were not found in the hairy roots. The present study suggested that co-expression of bHLH and MYB genes managed to induce the anthocyanin biosynthesis in both plants, tobacco and morning glory. Further work is required to illustrate the method which can be successfully used in more plants and produce more complex anthocyanin compounds.