Journal of Pest Science (2022) 95, 1163-1177

Marianna Stavrakaki, Aris Ilias, Panagiotis Ioannidis, John Vontas and Emmanouil Roditakis (2022)
Investigating mechanisms associated with emamectin benzoate resistance in the tomato borer Tuta absoluta
Journal of Pest Science 95 (3), 1163-1177
Abstract: 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.
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Link to article at publishers website
Database assignments for author(s): John Vontas, Emmanouil Roditakis

Research topic(s) for pests/diseases/weeds:
pesticide resistance of pest

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Phthorimaea absoluta	Tomato (Solanum lycopersicum)	Greece