Salt Stress-Induced Anthocyanin Biosynthesis Genes and MATE Transporter Involved in Anthocyanin Accumulation in Daucus carota Cell Culture

Anthocyanins biosynthesis is a well-studied biosynthesis pathway in Daucus carota. However, the scale-up production at the bioreactor level and transporter involved in accumulation is poorly understood. To increase anthocyanin content and elucidate the molecular mechanism involved in accumulation, we examined D. carota cell culture in flask and bioreactor for 18 days under salt stress (20.0 mM NH4NO3/37.6 mM KNO3) at 3 day intervals. The expression of anthocyanin biosynthesis and putative MATE (multidrug and toxic compound extrusion) transporter expression was analyzed by qRT-PCR. It was observed that there was a significant enhancement of anthocyanin in the bioreactor compared to the control culture. A correlation was observed between the expression of MATE and the anthocyanin biosynthesis genes (CHS, C4H, LDOX, and UFGT) on the 9th day in a bioreactor, where maximum anthocyanin accumulation and expression was detected. We hypothesize the involvement of MATE in transporting anthocyanin to tonoplast in D. carota culture under salt stress.