Insight into the Phytoremediation Capability of <i>Brassica juncea</i> (v. Malopolska): Metal Accumulation and Antioxidant Enzyme Activity

• Main Authors: Arleta Małecka, Agnieszka Konkolewska, Anetta Hanć, Danuta Barałkiewicz, Liliana Ciszewska, Ewelina Ratajczak, Aleksandra Maria Staszak, Hanna Kmita, Wiesława Jarmuszkiewicz
• Format: Article
• Language: English
• Published: MDPI AG 2019-09-01
• Series: International Journal of Molecular Sciences
• Subjects: oxidative stress; antioxidative system; Brassicaceae family; heavy metals
• Online Access: https://www.mdpi.com/1422-0067/20/18/4355

Metal hyperaccumulating plants should have extremely efficient defense mechanisms, enabling growth and development in a polluted environment. <i>Brassica</i> species are known to display hyperaccumulation capability. <i>Brassica juncea</i> (Indiana mustard) v. Malopolska plants were exposed to trace elements, i.e., cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn), at a concentration of 50 &#956;M and were then harvested after 96 h for analysis. We observed a high index of tolerance (IT), higher than 90%, for all <i>B. juncea</i> plants treated with the four metals, and we showed that Cd, Cu, Pb, and Zn accumulation was higher in the above-ground parts than in the roots. We estimated the metal effects on the generation of reactive oxygen species (ROS) and the levels of protein oxidation, as well as on the activity and gene expression of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX). The obtained results indicate that organo-specific ROS generation was higher in plants exposed to essential metal elements (i.e., Cu and Zn), compared with non-essential ones (i.e., Cd and Pb), in conjunction with SOD, CAT, and APX activity and expression at the level of encoding mRNAs and existing proteins. In addition to the potential usefulness of <i>B. juncea</i> in the phytoremediation process, the data provide important information concerning plant response to the presence of trace metals.