The tomato borer Tuta absoluta is a major pest of tomato mainly controlled by chemical insecticides. However, development of resistance to specific chemical classes has made control of the pest extremely difficult. Emamectin benzoate belongs to the avermectin mode of action and to date, low or no resistance levels against this insecticide have been documented. Recently, reduced efficacy of emamectin benzoate was documented, in a field population from Crete (ninefold resistant ratio (RR)). Subsequent laboratory selections with emamectin benzoate for eight sequential generations resulted in an increase of the RR to 60-fold, the highest resistance level reported to the particular insecticide. Hereby, we are presenting the characterization of emamectin benzoate resistance in T. absoluta. Sequencing of the GluCl and GABA receptor (rdl) genes, the molecular targets of emamectin benzoate indicted absence of non-synonymous SNPs. The use of known enzyme inhibitors (PBO, DEF and DEM) revealed that P450s partially synergized emamectin benzoate resistance, suggesting potential implication of metabolic resistance. RNAseq approach was used to identify differentially expressed genes, from emamectin benzoate resistant and susceptible T. absoluta populations. Twelve libraries were sequenced using the Illumina platform, which generated 81 Gbp, thus substantially increasing the number of publicly available genomic resources for this species. The de novo transcriptome assembly consisted of 549,601 contigs, grouped in 233,453 unigenes. Differential expression analysis and qPCR validation revealed over-expression of one unigene similar to cytochrome P450 (Clan 4) potentially implicated in emamectin benzoate resistance, supporting further the involvement of P450s in the observed resistance phenotype.

番茄螟Tuta absoluta是番茄的主要害虫，主要受化学杀虫剂控制。然而，对特定化学类别的抗性的发展使害虫的控制变得极其困难。Emamectin benzoate 属于阿维菌素的作用方式，迄今为止，已记录了对该杀虫剂的低抗性或无抗性。最近，在来自克里特岛的田间人群中，甲维菌素苯甲酸酯的功效降低（九倍耐药率（RR））。随后的实验室选择使用 emamectin benzoate 连续八代，导致 RR 增加到 60 倍，这是对特定杀虫剂报告的最高抗性水平。在此，我们展示了T. absoluta中甲维菌素苯甲酸盐抗性的表征. GluCl 和 GABA 受体 (rdl) 基因的测序，emamectin benzoate 的分子靶标表明不存在非同义 SNP。已知酶抑制剂（PBO、DEF 和 DEM）的使用表明，P450s 部分协同甲维菌素苯甲酸盐抗性，表明代谢抗性的潜在含义。RNAseq 方法用于鉴定差异表达的基因，来自对甲维菌素苯甲酸盐具有抗性和易感性的T. absoluta人口。使用 Illumina 平台对 12 个文库进行了测序，产生了 81 Gbp，从而大大增加了该物种的公开可用基因组资源的数量。从头转录组组装由 549,601 个重叠群组成，分为 233,453 个 unigenes。差异表达分析和 qPCR 验证揭示了一种类似于细胞色素 P450（Clan 4）的 unigene 的过度表达，可能与甲维菌素苯甲酸盐抗性有关，进一步支持 P450s 参与观察到的抗性表型。