Characterization of Anthocyanins Biosynthetic Genes and their Association with Cold Tolerance in Brassica

Flavonoids are divided into several structural classes, including anthocyanins, which provide flower and leaf colors and other derivatives with diverse roles in plant development and interactions with the environment. Induction of flavonoid metabolism is associated with the down-regulation of photosynthesis, hormonal responses and enhanced cold tolerance provide evidence for naturally increased nonacclimated cold tolerance due to the constitutive activation of the C-repeat binding factors (CBF) pathway and thereby correlate with cold tolerance. This study characterized 12 Dihydroflavonol 4-Reductase (DFR) and 4 Anthocyanidin Synthase (ANS) of Brassica rapa, structural genes of anthocyanin biosynthetic pathway, and investigated their association with cold tolerance in B. rapa. Sequences of these genes were analyzed and compared with similar types of gene sequences of other species and found a high degree of homology with their respective functions. In the organ specific expression analysis, these genes showed expression only in the colored portion of leaves of different lines of B. rapa. On the other hand, several genes among them showed differential expression with certain time course of cold stress treatment in B. rapa. The above results suggest that these genes have probable association with anthocyanin biosynthesis and cold tolerance and might be useful resources for developing cold resistant Brassica crops with desirable colors.