Active ingredients biosynthesis and genic response of traditional Chinese medicine Ligusticum sinense cv. Chuanxiong under different cadmium level

Ligusticum sinense cv. Chuanxiong (L. Chuanxiong), one of the most widely used traditional Chinese medicines, has been reported to suffer from cadmium (Cd) contamination. Thus, a genetic response to explain Cd transportation and resistance was necessary and critical for dealing with remediation. In this study, L. Chuanxiong was stressed by 0.13 (T0), 5 (T5) and 10 (T10) mg/kg Cd with comparative transcriptome analysis. Cd stored in L. Chuanxiong roots was c. 15 times higher than in aboveground plant parts. Zinc-regulated transporters (ZRT) and ABC-binding cassette transporters (ABC) genes were the major Cd-carriers in L. Chuanxiong cell wall. Moreover, the higher the Cd level, the more significantly up-regulated expression of ZRT and ABC. Metallothioneins (MTs) and Glutathione (GSH) genes were involved in Cd-binding inside L. Chuanxiong cells. Furthermore, Cd adsorption induced the genes related to cell antioxidant activities such as peroxidase, heat shock proteins and peptide methiomine sulfoxide reductase to deal with reactive oxygen species (ROS) damage, and the expression of those genes increased as Cd level increased. Biosynthesis of the activate ingredients ferulic acid in L. Chuanxiong was greatly influenced by Cd stress, presenting as the first key enzymes (phenylalanine ammonia-lyase) significantly down-regulated. These novel findings provide a theoretical basis for Cd-control in medicinal plants.