Arsenic-induced differential expression of oxidative stress and secondary metabolite content in two genotypes of Andrographis paniculata.

The present study explores the differential responses of two genotypes (APw: wild collection and AP: mass selection line) of A. paniculata against the three application rates of arsenic (42, 126, and 200 mg kg). The oxidative enzymes, As accumulation in different tissues, plant growth, and content of pharmacologically important ent-labdane-related diterpenes (ent-LRDs) of the two genotypes were evaluated in the study. Results demonstrated that As uptake significantly reduced plant biomass in APw and AP by 5-41.5% and 9-33% in a dose-response manner, respectively. The AP exhibited lower bioconcentration and translocation factors, higher As tolerance index, and higher content of ent-LRDs as compared to AP. As treatment induced a decrease in the sum of four metabolite content of AP (1.43 times) and an increase in that of AP (1.12 times) as compared to control. Likewise, variance in the production of 5,7,2',3'-tetramethoxyflavanone, and stress enzymes was also observed between APw and AP. The increase in the expression of ApCPS2 suggested its involvement in channeling of metabolic flux towards the biosynthesis of ent-LRDs under As stress.