Copper-caused oxidative stress triggers the activation of antioxidant enzymes via ZmMPK3 in maize leaves

Abstract

Copper (Cu) is a necessary trace element participated in many physiological processes in plants. But excessive Cu2+ is toxic, which can activate intracellular signals that lead to cellular damage. The mitogen-activated protein kinase (MAPK) cascade is at the center of cell signal transduction and has been reported to be involved in stress-related signaling pathways. ZmMPK3, a kind of MAPKs in maize cells, can be activated by diverse abiotic stresses. In the present study, we investigated the effects of Cu2+ on hydrogen peroxide (H2O2) level, ZmMPK3 activity as well as the activities of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and ascorbic acid peroxidase (APX) using maize leaf as an experimental model. The results demonstrated that acute Cu2+ exposure for 24 hours led to rapid increases of H2O2 level and the increase in ZmMPK3 activity as well as the total activities of antioxidant enzymes SOD, CAT and APX. H2O2 scavenger, dimethylthiourea (DMTU), effectively inhibited the Cu2+-increased H2O2 level and the activity of ZmMPK3 as well as the activities of the antioxidant enzymes SOD, CAT and APX. Pre-treatment with the MAPK inhibitor, PD98059, significantly blocked the Cu2+-increased activities of ZmMPK3, CAT, APX and SOD, but didn’t affect the accumulation of H2O2. Our results suggest that Cu2+ causes oxidative stress to the maize leaves which then activates defense antioxidant enzymes via MAPK pathway. Thus, the signaling pathway is Cu2+—H2O2—ZmMPK3—antioxidant enzymes.

Physiological and Biochemical Properties of Cotton in Response to Copper Stress

“…In this study, increasing Cu concentration in culture medium led to the increase in H 2 O 2 and MDA in the leaves of cotton seedling Fig.3A . The results were in harmony with ndings of previous studies in maize leaves (Liu et al, 2018) and in Medicago sativa seedling shoot [17] In this current study, Cu induced H 2 O 2 incited directly lipid membrane damage in cotton leaves. High concentration of ROS caused enzyme inactivation, lipid peroxidation, and oxidation of nucleic acids [18].…”

“…The accumulation of H 2 O 2 in leaves was measured by monitoring the A415 of the titanium-peroxide complex following the method described by Liu et al [28]. Absorbance values were calibrated to a standard curve generated with known concentrations of H 2 O 2 .…”

Copper Uptake and Accumulation, Ultra-Structural Alteration, and Bast Fibre Yield and Quality of Fibrous Jute (Corchorus capsularis L.) Plants Grown under Two Different Soils of China

“…However, previously we reported that jute could tolerate the Cu level up to 300 mg kg −1 and Cu contents more than 300 mg kg −1 in the soil caused decreased in plant growth [46]. This might be due to the high level of Cu accumulated in the cells, which affects the plant growth and development [7,17]. Another reason behind this mechanism is also due to the reduction in essential elements in the soil and an increased in Cu contents in plant cells, causing chlorotic symptoms [47].…”

“…Furthermore, normal concentration of Cu is nontoxic to plants, whereas Cu toxicity directly disturbs the structure of chloroplast, mitochondrial apparatus, nucleus, and other cellular organelles [6,7,13,14]. Excess Cu causes damage to the cellular membrane organelles by increasing ROS in plant cells and tissues, causing peroxidation of substances on the cell surface [11,[15][16][17]. ROS, which are toxic and remove by the activities of antioxidant compounds [18][19][20][21][22][23].…”

An Overview of Hazardous Impacts of Soil Salinity in Crops, Tolerance Mechanisms, and Amelioration through Selenium Supplementation

“…Under salinity stress, the exogenous supplementation of Se to maize (Zea maize L.) plants resulted in the upregulation of expression of mitogen activated protein kinase (MAPK5 and MAPK7) and calcium-dependent protein kinase (CPK11) genes and stimulated the antioxidant defense system under salt stress [29,163]. It has been reported that MAPK flow is at the center of cell signal transduction and implicated in stress-related signal pathways [164]. Abscisic acid (ABA) accumulation could be stimulated under salinity stress [165], which in turn produces H 2 O 2 , causing the activation of MAPK, resulting in stimulated expression and activities of antioxidant enzymes [166].…”