Protein Carbonylation As a Biomarker of Heavy Metal, Cd and Pb, Damage in Paspalum fasciculatum Willd. ex Flüggé

Abstract

Heavy metal tolerant plants have phytoremediation potential for the recovery of contaminated soils, and the characterization of their metabolic adaptation processes is an important starting point to elucidate their tolerance mechanisms at molecular, biochemical and physiological levels. In this research, the effects of Cd and Pb on growth and protein carbonylation in tissues of Paspalum fasciculatum exposed to 30 and 50 mg·Kg−1 Cd and Pb respectively were determined. P. fasciculatum seedlings exposed to metals grew more than controls until 60 days of cultivation and limited their oxidative effects to a reduced protein group. Carbonyl indexes in leaf and root proteins reached a significant increase concerning their controls in plants exposed 30 days to Cd and 60 days to Pb. From the combined approach of Western Blot with Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) and protein analysis by Matrix Asisted Laser Desorption/Ionisation-Time Of Flight (MALDI-TOF/TOF) mass spectrometry, chloroplastic proteins were identified into the main oxidative stress-inducible proteins to Cd and Pb, such as subunits α, γ of ATP synthetase, Chlorophyll CP26 binding protein, fructose-bisphosphate aldolase and long-chain ribulose bisphosphate carboxylase (RuBisCO LSU). Cd generated damage in the photosynthetic machinery of the leaves of P. fasciculatum into the first 30 days of treatment; five of the oxidized proteins are involved in photosynthesis processes. Moreover, there was a proteolytic fragmentation of the RuBisCO LSU. Results showed that intrinsic tolerance of P. fasciculatum to these metals reached 60 days in our conditions, along with the bioaccumulating appreciable quantities of metals in their roots.

Phytostabilization of Pb-Zn Mine Tailings with Amorpha fruticosa Aided by Organic Amendments and Triple Superphosphate

“…In order to scavenge ROS and avoid oxidative stress, plants produce and activate different antioxidant enzymes like catalase (CAT), phenylalanine ammonialyase (PAL) and polyphenol oxidase (PPO) as a defense mechanism [28]. Like antioxidant enzymes, soluble proteins also play an important role in plant defense system by regulating the osmotic balance, stabilizing macromolecules, quenching ROS and preventing oxidative damage, and thereby are considered as bioindicators of metal stress [29][30][31]. Hence, it is important to evaluate the physiological defensive capacity of plants under metal stress for successful phytoremediation processes.…”

Proteomic Changes in Paspalum fasciculatum Leaves Exposed to Cd Stress

“…They aid in folding and degradation, and act on misfolded proteins that have lost their normal assembly [ 3 ]. ROS are responsible for a large part of the damaging effects on proteins caused by Cd stress in P. fasciculatum leaves [ 25 ].…”

“…P. fasciculatum plants were propagated from cuttings (5 cm) obtained from individuals of 1 m in length and grown in metal-free soil [ 25 , 26 ]. Three weeks after cut-sowing, plantlets were transferred to the soil from the “Alacrán” mine (northwestern Colombia, 7°44′29.0″ N and 75°44′10.8″ W) ( Table S2 ).…”

“…Ex. Flüggé—a plant of the Poaceae family that is widely distributed in tropical and subtropical ecosystems, and can grow in mining soils with high levels of contamination by the heavy metals Cd and Pb thanks to its phytoremediation and phytoextraction characteristics [ 25 ]. Similar to other plants, it also exhibits an antioxidant response, limiting the oxidative damage to its proteome promoted by these metals [ 26 ].…”