Involvement of several putative transporters of different families in β-cyclocitral-induced alleviation of cadmium toxicity in quinoa (Chenopodium quinoa) seedlings.

Abstract Cadmium (Cd) has a serious negative impact on crop growth and human food security. This study investigated the alleviating effect of β-cyclocitral, a potential heavy metal barrier, on Cd stress in quinoa seedlings and the associated mechanisms. Our results showed that β-cyclocitral alleviated Cd stress-induced growth inhibition in quinoa seedlings and promoted quinoa seedling root development under Cd stress. Moreover, it maintained the antioxidant system of quinoa seedlings, including the enzymatic, i.e., superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), and nonenzymatic, i.e., reduced glutathione (GSH) and ascorbic acid (ASA), antioxidants, which eliminate the damage from excessive reactive oxygen species (ROS). Our results showed that β-cyclocitral could reduce the amount of Cd absorbed by roots. Furthermore, we systematically identified five transporter families from the quinoa genome, and the RT-qPCR results showed that ZIP, Nramp and YSL gene families were downregulated by β-cyclocitral to reduce Cd uptake by roots. Thus, β-cyclocitral promoted the growth, photosynthetic capacity and antioxidant capacity of the aboveground parts of quinoa seedlings. Taken together, these results suggested that the β-cyclocitral-induced decrease in Cd uptake may be caused by the downregulation of several selected transporter genes.