Secretory class III peroxidases are involved in plant responses to a range of biological stress conditions, including oxidative stress. To investigate the stress-related functions of the swpa4 peroxidase gene in sweetpotato (Ipomoea batatas L.), transgenic plants overexpressing the swpa4 gene under the control of the CaMV 35S promoter were generated using Agrobacterium-mediated transformation. Peroxidase activity was 3- to 13-fold higher in transgenic lines than in control plants. Transgenic plants were tested for tolerance to stress. Following treatment with 400 mM hydrogen peroxide (H₂O₂), leaf discs from transgenic plants showed approximately 13–26% less damage than control plants. Transgenic plants also showed enhanced tolerance to high salinity conditions. Following treatment with NaCl, photosynthetic capacity and total chlorophyll contents were less severely impacted in swpa4 transgenic plants than in control plants. Aerial plant parts and storage root yields were not significantly different between transgenic and control plants following cultivation in field conditions. These results indicate that transgenic sweetpotato lines were able to respond efficiently to oxidative and saline stress via overexpression of swpa4.

中文翻译：

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swpa4过氧化物酶的过表达增强了转基因甘薯植物对过氧化氢和高盐度介导的氧化胁迫的耐受性

分泌型III类过氧化物酶参与植物对一系列生物胁迫条件（包括氧化胁迫）的反应。为了研究swpa4过氧化物酶基因在甘薯（Ipomoea batatas L.）中与胁迫相关的功能，使用农杆菌介导的转化产生了在CaMV 35S启动子控制下过表达swpa4基因的转基因植物。转基因品系中的过氧化物酶活性比对照植物高3至13倍。测试转基因植物对胁迫的耐受性。用400 mM过氧化氢（H ₂ O ₂），转基因植物的叶盘显示出比对照植物少约13–26％的损害。转基因植物还显示出对高盐度条件的增强的耐受性。用氯化钠处理后，与对照植物相比，swpa4转基因植物对光合能力和总叶绿素含量的影响较小。在田间条件下种植后，转基因植物和对照植物之间的空中植物部分和贮藏根产量没有显着差异。这些结果表明，转基因甘薯品系能够通过过表达swpa4来有效响应氧化和盐胁迫。