Like conventional crops, transgenic plants expressing insecticidal toxins from Bacillus thuringiensis (Bt) are subjected to water deprivation. However, the effects of water deprivation over the insecticidal activity of Bt plants are not well understood. We submitted Bt maize and Bt soybean to water deprivation and evaluated biochemical stress markers and the insecticidal activity of plants against target insects. Bt maize (DAS-Ø15Ø7-1 × MON-89Ø34-3 × MON-ØØ6Ø3–6 × SYN-IR162-4) containing the PowerCore Ultra traits, Bt soybean (DAS-444Ø6-6 × DAS-81419-2) with the Conkesta E3 traits, and commercial non-Bt cultivars were cultivated and exposed to water deprivation in the greenhouse. Leaves were harvested for quantification of hydrogen peroxide, malondialdeyde (MDA), and total phenolics and insecticidal activity. Maize or soybean leaf disks were used to evaluate the insecticidal activity against, respectively, Spodoptera frugiperda (J.E Smith) and Chrysodeixis includens (Walker) neonates. Except for Bt soybean, water deprivation increased hydrogen peroxide and MDA contents in Bt and non-Bt plants. Both biochemical markers of water deficit were observed in lower concentrations in Bt plants than in non-Bt commercial cultivars. Water deprivation did not result in changes of phenolic contents in Bt and non-Bt maize. For Bt or non-Bt soybean, phenolic contents were similar despite plants being exposed or not to water deprivation. Water deprivation did not alter substantially insect survival in non-Bt maize or non-Bt soybean. Despite water deprivation-induced biochemical changes in plants, both Bt plants maintained their insecticidal activity (100% mortality) against the target species.

中文翻译：

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缺水会引起生化变化，但不会降低玉米和大豆转基因植物的杀虫活性


与传统作物一样，表达苏云金芽孢杆菌 (Bt) 杀虫毒素的转基因植物也会遭受缺水。然而，缺水对 Bt 植物杀虫活性的影响尚不清楚。我们将 Bt 玉米和 Bt 大豆置于缺水条件下，评估生化胁迫标记和植物对目标昆虫的杀虫活性。含有 PowerCore Ultra 性状的 Bt 玉米 (DAS-Ø15Ø7-1 × MON-89Ø34-3 × MON-ØØ6Ø3–6 × SYN-IR162-4)，Bt 大豆 (DAS-444Ø6-6 × DAS-81419-2)在温室中培育 Conkesta E3 性状和商业非 Bt 品种并暴露在缺水条件下。收获叶子以定量测定过氧化氢、丙二醛 (MDA) 以及总酚类和杀虫活性。使用玉米或大豆叶盘分别评估对草地贪夜蛾 (JE Smith) 和 Chrysodeixis includens (Walker) 新生儿的杀虫活性。除 Bt ​​大豆外，缺水会增加 Bt 和非 Bt 植物中过氧化氢和 MDA 的含量。在 Bt 植物中观察到的两种缺水生化标志物的浓度均低于非 Bt 商业品种。缺水不会导致 Bt 和非 Bt 玉米中酚含量的变化。对于 Bt 或非 Bt 大豆，无论植物是否处于缺水状态，酚类含量都相似。缺水并没有显着改变非 Bt 玉米或非 Bt 大豆中昆虫的存活率。尽管缺水会导致植物发生生化变化，但这两种 Bt 植物仍保持了对目标物种的杀虫活性（100% 死亡率）。