State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China; Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environmental and Civil Engineering, Jiangnan University, Wuxi, 214122, China.
State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China; Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environmental and Civil Engineering, Jiangnan University, Wuxi, 214122, China; Jiangsu Cooperative Innovation Center of Technology and Material of Water Treatment, Jiangnan University, Wuxi, 214122, China.
Ecotoxicol Environ Saf. 2020 Apr 15;193:110351. doi: 10.1016/j.ecoenv.2020.110351. Epub 2020 Feb 25.
Microcystins (MCs) have become an important global environmental issue, causing oxidative stress, which is an important toxic mechanism for MCs in plants. However, the regulating mechanism of antioxidative enzymes in plants in adapting to MCs stress remains unclear. We studied the dynamic effects of MCs at different concentrations (5, 10, 50 and 100 μg/L) in rice and cucumber seedlings on relative growth rate (RGR), and reactive oxygen species and malondialdehyde (MDA) content, and antioxidative enzyme activities, during a stress period (MCs exposed for 1, 3, 5 and 7 d) and recovery period (7 d). During the stress period, MCs at 5 μg/L inhibited RGR in cucumber and promoted RGR in rice. The contents of superoxide anion (O·), hydrogen peroxide (HO) and MDA increased and RGR declined in both crops with time and intensity of MCs stress. For cucumber, all these parameters responded earlier to MCs stress, and O·, MDA and RGR were more responsive to MCs stress than in rice. Moreover, catalase (CAT) and peroxidase (POD), and the relative expressions of CAT genes increased in both crops at 5-100 μg/L MCs, whereas relative expression of POD genes increased only in cucumber. Diversely, superoxide dismutase (SOD) response to MCs in cucumber leaves was later than for rice. MCs at 100 μg/L decreased the relative expression of SOD genes in cucumber but did not change SOD activity. During the recovery period, all the above indicators in both crops were higher than the control and lower than in the stress period. Conversely, RGR was lower than in the control and higher than in the stress period, except for cucumber which was lower, and MDA content higher than the stress period at 100 μg/L MCs. Overall, these results indicated that cucumber was more sensitive to MCs than rice, and SOD, CAT and POD play an important role in plant response to MCs stress.
微囊藻毒素（MCs）已成为一个重要的全球性环境问题，导致氧化应激，这是 MCs 在植物中产生毒性的一个重要机制。然而，植物适应 MCs 胁迫的抗氧化酶的调节机制尚不清楚。我们研究了不同浓度（5、10、50 和 100μg/L）的 MCs 在水稻和黄瓜幼苗中的动态效应，以及在胁迫期（MCs 暴露 1、3、5 和 7d）和恢复期（7d）内相对生长率（RGR）、活性氧和丙二醛（MDA）含量以及抗氧化酶活性的变化。在胁迫期内，5μg/L 的 MCs 抑制了黄瓜的 RGR，促进了水稻的 RGR。随着时间的推移和 MCs 胁迫的强度的增加，两种作物中超氧阴离子（O·）、过氧化氢（HO）和 MDA 的含量增加，RGR 下降。对于黄瓜，所有这些参数对 MCs 胁迫的响应更早，O·、MDA 和 RGR 对 MCs 胁迫的响应比对水稻更敏感。此外，CAT 和 POD 以及 CAT 基因的相对表达在两种作物中都随着 5-100μg/L MCs 的增加而增加，而 POD 基因的相对表达仅在黄瓜中增加。相反，黄瓜叶片中 SOD 对 MCs 的反应比水稻晚。100μg/L 的 MCs 降低了黄瓜中 SOD 基因的相对表达，但并未改变 SOD 活性。在恢复期内，两种作物的所有上述指标均高于对照，低于胁迫期。相反，RGR 低于对照，高于胁迫期，除了 100μg/L MCs 时的黄瓜低于胁迫期外，MDA 含量也高于胁迫期。总的来说，这些结果表明，黄瓜比水稻对 MCs 更敏感，SOD、CAT 和 POD 在植物对 MCs 胁迫的反应中发挥着重要作用。
