Department of Genetics, University of Valencia, Burjassot, Valencia, Spain.
PLoS One. 2013 Dec 2;8(12):e81927. doi: 10.1371/journal.pone.0081927. eCollection 2013.
Host-pathogen interactions result in complex relationship, many aspects of which are not completely understood. Vip proteins, which are Bacillus thuringensis (Bt) insecticidal toxins produced during the vegetative stage, are selectively effective against specific insect pests. This new group of Bt proteins represents an interesting alternative to the classical Bt Cry toxins because current data suggests that they do not share the same mode of action. We have designed and developed a genome-wide microarray for the beet armyworm Spodoptera exigua, a serious lepidopteran pest of many agricultural crops, and used it to better understand how lepidopteran larvae respond to the treatment with the insecticidal protein Vip3Aa. With this approach, the goal of our study was to evaluate the changes in gene expression levels caused by treatment with sublethal doses of Vip3Aa (causing 99% growth inhibition) at 8 and 24 h after feeding. Results indicated that the toxin provoked a wide transcriptional response, with 19% of the microarray unigenes responding significantly to treatment. The number of up- and down-regulated unigenes was very similar. The number of genes whose expression was regulated at 8 h was similar to the number of genes whose expression was regulated after 24 h of treatment. The up-regulated sequences were enriched for genes involved in innate immune response and in pathogen response such as antimicrobial peptides (AMPs) and repat genes. The down-regulated sequences were mainly unigenes with homology to genes involved in metabolism. Genes related to the mode of action of Bt Cry proteins were found, in general, to be slightly overexpressed. The present study is the first genome-wide analysis of the response of lepidopteran insects to Vip3Aa intoxication. An insight into the molecular mechanisms and components related to Vip intoxication will allow designing of more effective management strategies for pest control.
宿主-病原体相互作用导致复杂的关系，其中许多方面尚未完全理解。在营养阶段产生的苏云金芽孢杆菌（Bt）杀虫毒素 Vip 蛋白对特定的鳞翅目害虫具有选择性的有效性。这组新的 Bt 蛋白代表了一种有趣的替代经典 Bt Cry 毒素的选择，因为目前的数据表明它们不具有相同的作用模式。我们设计并开发了甜菜夜蛾 Spodoptera exigua 的全基因组微阵列，甜菜夜蛾是许多农业作物的严重鳞翅目害虫，并使用它来更好地了解鳞翅目幼虫如何对杀虫蛋白 Vip3Aa 的处理做出反应。通过这种方法，我们研究的目标是评估用亚致死剂量的 Vip3Aa（导致 99%生长抑制）处理后 8 和 24 小时喂食时引起的基因表达水平的变化。结果表明，毒素引起了广泛的转录反应，微阵列的 19%非编码基因对处理有显著反应。上调和下调的非编码基因数量非常相似。在 8 小时表达受调控的基因数量与 24 小时处理后表达受调控的基因数量相似。上调的序列富含参与先天免疫反应和病原体反应的基因，如抗菌肽（AMPs）和 repat 基因。下调的序列主要是与代谢相关的基因的非编码基因。一般来说，与 Bt Cry 蛋白作用模式相关的基因被发现略微过表达。本研究是鳞翅目昆虫对 Vip3Aa 中毒反应的首次全基因组分析。深入了解与 Vip 中毒相关的分子机制和成分将允许设计更有效的害虫管理策略。
