Pink bollworm (PBW), Pectinophora gossypiella, is one of the most destructive insect pests of cotton worldwide. In India, PBW has developed widespread resistance to the Cry1Ac and Cry2Ab toxins of Bt Bollgard II cotton. To understand the molecular mechanism of Bt resistance, the midgut transcriptome of an Indian strain of Bt‐susceptible (PBW‐BtS) and Bt‐resistant (PBW‐BtR) PBW larvae were sequenced using Illumina platform to identify the genes and pathways associated with Bt resistance. A total of 31,764 unique unigenes were assembled from all the four samples, and 1,741 unigenes were found to be differentially expressed between PBW‐BtS and PBW‐BtR, out of which 1,024 unigenes were down‐regulated and 717 were up‐regulated. Down‐regulated genes associated with already known Bt resistance genes in different organisms included APN, ABCA, ABCG8 and cadherin. On the other hand, unigenes related to metabolic resistance such as cytochrome P450, GST and carboxylesterase were up‐regulated in PBW‐BtR when compared with PBW‐BtS. Moreover, real‐time quantitative results of randomly selected genes confirmed the transcriptome response. This is the first comparative transcriptome study to identify the candidate genes involved in Bt BG II resistance in pink bollworm. We believe that the assembled and annotated transcriptome will serve as a valuable resource for future studies to discern the molecular basis of PBW Bollgard II resistance.

中文翻译：

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Pectinophora gossypiella 对印度 Bt Bollgard II 棉花田间进化抗性的转录组改变

粉红铃虫（PBW），Pectinophora gossypiella，是世界范围内对棉花最具破坏性的害虫之一。在印度，PBW 已经对 Bt Bollgard II 棉花的 Cry1Ac 和 Cry2Ab 毒素产生了广泛的抗性。为了了解 Bt 抗性的分子机制，使用 Illumina 平台对印度 Bt 易感 (PBW-BtS) 和 Bt 抗性 (PBW-BtR) PBW 幼虫的中肠转录组进行测序，以确定与 Bt 相关的基因和途径抵抗性。从所有四个样品中总共组装了 31,764 个独特的 unigenes，发现 1,741 个 unigenes 在 PBW-BtS 和 PBW-BtR 之间差异表达，其中 1,024 个 unigenes 下调，717 个上调。与不同生物体中已知的 Bt 抗性基因相关的下调基因包括 APN、ABCA、ABCG8 和钙粘蛋白。另一方面，与 PBW-BtS 相比，与代谢抗性相关的 unigenes，如细胞色素 P450、GST 和羧酸酯酶在 PBW-BtR 中上调。此外，随机选择基因的实时定量结果证实了转录组反应。这是第一个比较转录组研究，以确定与粉红铃虫 Bt BG II 抗性相关的候选基因。我们相信组装和注释的转录组将作为未来研究的宝贵资源，以识别 PBW Bollgard II 抗性的分子基础。随机选择基因的实时定量结果证实了转录组反应。这是第一个比较转录组研究，以确定与粉红铃虫 Bt BG II 抗性相关的候选基因。我们相信组装和注释的转录组将作为未来研究的宝贵资源，以识别 PBW Bollgard II 抗性的分子基础。随机选择基因的实时定量结果证实了转录组反应。这是第一个比较转录组研究，以确定与粉红铃虫 Bt BG II 抗性相关的候选基因。我们相信组装和注释的转录组将作为未来研究的宝贵资源，以识别 PBW Bollgard II 抗性的分子基础。