Molybdenum Supply Alleviates the Cadmium Toxicity in Fragrant Rice by Modulating Oxidative Stress and Antioxidant Gene Expression

Abstract

Increasing evidence shows that cadmium (Cd) toxicity causes severe perturbations on growth performance, physio-biochemical and molecular processes in crop plants. Molybdenum (Mo), an essential trace element, plays key roles in oxidative stress tolerance of higher plants. Hence, the present study has been conducted to investigate the possible role of Mo in alleviating Cd-induced inhibitions in two fragrant rice cultivars namely Guixiangzhan (GXZ) and Meixiangzhan-2 (MXZ-2). The results revealed that Mo application enhanced the plant dry biomass by 73.24% in GXZ and 58.09% in MXZ-2 under Cd stress conditions, suggesting that Mo supplementation alleviated Cd-induced toxicity effects in fragrant rice. The enhanced Cd-tolerance in fragrant rice plants prompted by Mo application could be ascribed to its ability to regulate Cd uptake and reduce Cd-induced oxidative stress as evident by lower hydrogen peroxide levels, electrolyte leakage and malondialdehyde contents in Cd-stressed plants. The ameliorative role of Mo against Cd-toxicity also reflected through its protection to the photosynthetic pigments, proline and soluble protein. Mo also induced antioxidant defense systems via maintaining higher contents of glutathione and ascorbate as well as enhancing the ROS-detoxifying enzymes such as catalase, peroxidase, superoxide dismutase and ascorbate peroxidase activities and up-regulating transcript abundance in both fragrant rice cultivars under Cd stress. Conclusively, Mo-mediated modulation of Cd toxicity in fragrant rice was through restricting Cd uptake, maintaining photosynthetic performance and alleviating oxidative damages via the strong anti-oxidative defense systems; however, GXZ cultivar is comparatively more Cd tolerant and Mo-efficient as evident from the less growth inhibition and biomass reduction as well as enhanced Mo-induced Cd stress tolerance and less oxidative damage than MXZ-2 fragrant rice cultivar.

Role of Ferrous Sulfate (FeSO4) in Resistance to Cadmium Stress in Two Rice (Oryza sativa L.) Genotypes

“…Different practices have been used for the management of Cd-contaminated soils and its reduction in crop plants [ 2 , 13 ]. There are several studies that reported that the application of elements such as iron (Fe), nitrogen (N), zinc (Zn), selenium (Se), and phosphorus (P) could decrease Cd uptake and toxicity in O. sativa [ 46 , 52 ].…”

“…Heavy metals include cadmium (Cd), lead (Pb), nickel (Ni), cobalt (Co), iron (Fe), zinc (Zn), chromium (Cr), iron (Fe), arsenic (As), silver (Ag) and the platinum group elements. Contamination of agricultural soils with Cd has become one of the most toxic and widespread environmental problems [ 13 ]. Cd is mainly entered into the ecosystem through human activities such as agricultural practices and mining activities [ 14 , 15 ].…”

Silymarin-Enriched Biostimulant Foliar Application Minimizes the Toxicity of Cadmium in Maize by Suppressing Oxidative Stress and Elevating Antioxidant Gene Expression

“…Crop plants must be qualified to cope with the adverse effects of heavy metals using novel strategies to minimize plant uptake or increase the plant’s resistance to their massive damage. Farmland contaminated with heavy metals is causing a dangerous decline in the efficiency of processes in plants concerning growth and productivity [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ]. The increase in heavy metals in the soil stimulates oxidative stress linked to the overproduction of ROSs (reactive species of oxygen radicals).…”

“…The increase in heavy metals in the soil stimulates oxidative stress linked to the overproduction of ROSs (reactive species of oxygen radicals). ROSs threaten plants by endangering various pathways related to both physiobiochemistry and molecular biology [ 8 , 9 , 10 ]. The decrease in plant growth due to heavy metals depends on some factors, including plant species, heavy metal concentration, growth conditions, and experimental conditions [ 11 , 12 ].…”

Peptone-Induced Physio-Biochemical Modulations Reduce Cadmium Toxicity and Accumulation in Spinach (Spinacia oleracea L.)

“…These results were in agreement with that previously reported [ 35 ]. Previous reports have revealed that the environmental stresses considerably induce oxidative stress as well as the levels of electrolyte leakage (EL) and malondialdehyde (MDA) in different plant species, causing damages in plant tissues [ 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 ]. Similarly, in the current study, spinach plants also exhibited higher levels of EL and MDA in the absence of peptone treatment.…”