Department of Biology and Biotechnology, University of Pavia, Pavia, Italy.
School of Bioscience and Veterinary Medicine, University of Camerino, Camerino, Italy.
Sci Rep. 2017 Jan 23;7:41312. doi: 10.1038/srep41312.
Animals respond to chemical stress with an array of gene families and pathways termed "chemical defensome". In arthropods, despite many defensome genes have been detected, how their activation is arranged during toxic exposure remains poorly understood. Here, we sequenced the transcriptome of Anopheles stephensi larvae exposed for six, 24 and 48 hours to the LD dose of the insecticide permethrin to monitor transcriptional changes of defensome genes across time. A total of 177 genes involved in insecticide defense were differentially expressed (DE) in at least one time-point, including genes encoding for Phase 0, I, II, III and antioxidant enzymes and for Heat Shock and Cuticular Proteins. Three major patterns emerged throughout time. First, most of DE genes were down-regulated at all time-points, suggesting a reallocation of energetic resources during insecticide stress. Second, single genes and clusters of genes turn off and on from six to 48 hours of treatment, showing a modulated response across time. Third, the number of up-regulated genes peaked at six hours and then decreased during exposure. Our results give a first picture of how defensome gene families respond against toxicants and provide a valuable resource for understanding how defensome genes work together during insecticide stress.
动物会通过一系列被称为“化学防御组”的基因家族和途径来应对化学应激。在节肢动物中，尽管已经检测到许多防御组基因，但它们在受到有毒物质暴露时的激活方式仍知之甚少。在这里，我们对经 LD 剂量拟除虫菊酯处理 6、24 和 48 小时的斯氏按蚊幼虫进行了转录组测序，以监测防御组基因在整个时间过程中的转录变化。共有 177 个与杀虫剂防御有关的基因在至少一个时间点差异表达（DE），包括编码相位 0、I、II、III 和抗氧化酶以及热休克蛋白和表皮蛋白的基因。随着时间的推移，出现了三种主要模式。首先，大多数 DE 基因在所有时间点均下调，表明在杀虫剂应激期间重新分配了能量资源。其次，单个基因和基因簇从 6 小时到 48 小时的处理时间关闭和打开，表现出随时间变化的调节反应。第三，上调基因的数量在 6 小时达到峰值，然后在暴露过程中减少。我们的研究结果首次描绘了防御组基因家族如何对有毒物质作出反应，并为了解防御组基因在杀虫剂应激期间如何协同工作提供了有价值的资源。
