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

Highlights: • Arsenic induced stress was evaluated in two genotypes (AP_WC and AP_MS) of A. paniculata. • AP_MS was found to be more tolerant and accumulate less As than AP_WC. • Arsenic modulates the micronutrient status, concentration of andrographolide, neoandrographolide, DDA, andrograpanin. • Arsenic enhanced the flavonoid (5,7,2′,3′-tetra methoxy flavanone) in the plant. • The expression of ApCPS2 was upregulated under As-stress. The present study explores the differential responses of two genotypes (APw_C: wild collection and AP_MS: mass selection line) of A. paniculata against the three application rates of arsenic (42, 126, and 200 mg kg⁻¹). 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_C and AP_MS by 5–41.5% and 9–33% in a dose-response manner, respectively. The AP_MS exhibited lower bioconcentration and translocation factors, higher As tolerance index, and higher content of ent-LRDs as compared to AP_WC. As treatment induced a decrease in the sum of four metabolite content of AP_MS (1.43 times) and an increase in that of AP_WC (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_C and AP_MS. The increase in the expression of ApCPS2 suggested its involvement in channeling of metabolic flux towards the biosynthesis of ent-LRDs under As stress.