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    复合种植模式下谷胱甘肽和GST2调控活性氧清除增强林下植物抗寒性

    Glutathione and GST2 regulating reactive oxygen species scavenging to enhance cold resistance of understory plants under intercropping patterns

    • 摘要:
      目的 本研究聚焦蓝靛果、木豆和黄芩的复合种植模式,探究其对林下植物抗低温胁迫能力的影响,并解析谷胱甘肽(GSH)及其代谢通路相关基因GST2在抗氧化防御中的作用。
      方法 采用复合种植与单独种植对比试验,测定正常温度(25 ℃)和低温胁迫(0 ℃)下植物体内H2O2、谷胱甘肽(GSH)含量及抗氧化酶(CAT、APX、GST、SOD、POD)活性变化。通过外源喷施GSH以及构建过表达谷胱甘肽转移酶2基因(GST2)载体,真空渗透瞬时转化到木豆植株中,进一步验证GSH和GST2在抗氧化防御中的作用机制。
      结果 复合种植显著提高林下植物的GSH含量及抗氧化酶活性。低温处理后,复合种植的蓝靛果、木豆、黄芩中H2O2含量分别降低16.04%、38.98%、10.10%,GSH含量分别提高7.63%、13.4%、8.85%,GST活性分别提高1.81倍、5.37倍、3.13倍。外源喷施GSH可增强木豆抗寒性,使H2O2含量下降19.89%,CAT、APX、GST酶活性分别提高14.81%、24.18%、14.24%,GSH含量提高37.48%。过表达GST2的木豆在低温胁迫下H2O2和MDA含量分别下降10.10%、14.73%,GSH含量提高10.68%,APX、SOD、POD酶活性显著增强。
      结论 复合种植通过提升谷胱甘肽(GSH)含量,激活抗坏血酸-谷胱甘肽(ASA-GSH)通路以协同清除活性氧(ROS);在此基础上,GST2基因的过表达进一步强化了该通路的运行效率,这2种机制的协同作用共同增强了林下植物的抗寒性。本研究为复合种植模式在抗寒栽培中的应用提供了理论依据。

       

      Abstract:
      Objective This study focused on the effects of the composite planting pattern of blue honeysuckle (Lonicera caerulea), pigeonpea (Cajanus cajan), and scutellaria (Scutellaria baicalensis) on the resistance of understory plants to low-temperature stress. The study also analyzed the roles of glutathione (GSH) and its metabolic pathway-related genes in antioxidant defense. We analyzed the role of glutathione and its metabolic pathway-related genes in antioxidant defense.
      Method We used compound and individual planting to determine changes in H2O2 and GSH content, as well as the activity of antioxidant enzymes (CAT, APX, GST, and POD), under normal (25 ℃) and low temperature (0 ℃) stress. We further verified the mechanism of GSH and GST2 in antioxidant defense by spraying GSH exogenously, as well as by constructing a vector for the overexpression of the glutathione transferase 2 (GST2) gene and transiently transforming it into wood bean plants via vacuum infiltration.
      Result Composite planting significantly increased GSH content and antioxidant enzyme activities in understory plants. After low-temperature treatment, H2O2 content decreased by 16.04%, 38.98%, and 10.10%; GSH content increased by 7.63%, 13.4%, and 8.85%; and GST activity increased 1.81, 5.37, and 3.13 fold, respectively, in the composite planting of blue honeysuckle, pigeonpea, and scutellaria. Exogenous GSH spraying enhanced pigeonpea's cold tolerance by decreasing H2O2 content by 19.89% and increasing CAT, APX, and GST enzyme activities by 14.81%, 24.18%, and 14.24%, respectively, as well as increasing GSH content by 37.48%. The H2O2 and MDA contents of pigeonpea overexpressing GST2 decreased by 10.10% and 14.73%, respectively. The GSH content increased by 10.68%. The activities of the APX, SOD, and POD enzymes were significantly enhanced under low-temperature stress.
      Conclusion Composite planting activates the glutathione-ascorbate (GSH-ASA) pathway by increasing GSH content, which synergistically scavenges reactive oxygen species (ROS). Overexpression of the GST2 gene enhances the antioxidant efficacy of this pathway. Together, they enhance the cold resistance of understory plants. This study establishes the theoretical basis for applying the composite planting model to cold-resistant cultivation.

       

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