To comprehend the underlying mechanisms contributing to insecticide resistance in Tuta absoluta, a solanaceous plant pest posing significant threats to tomato cultivation, a detailed study was conducted. This study focused on comparing the transcriptomic profiles of field-collected parental populations and F8 lab-reared populations of Tuta absoluta, or Phthorimaea absoluta as the official name is, particularly in response to diamides and avermectins, two commonly used insecticides. The investigation extended to examining gene expression levels related to organophosphate and pyrethroid resistance, specifically targeting acetylcholinesterase (ace1) and para-type voltage-gated sodium channel (VGSG) genes across F1 to F8 generations derived from field-collected P. absoluta exposed to diamides and avermectins.
Findings revealed an up-regulation of the VGSG gene in 12.5% of the populations, with a down-regulation observed in the remaining 87.5%. Conversely, the ace1 gene exhibited up-regulation in 37.5% of the populations and down-regulation in 62.5%. Gene ontology analysis pinpointed three genes involved in the metabolic detoxification of diamides within both parental and eighth-generation P. absoluta populations, suggesting these enzymes play a pivotal role in the development of diamide resistance. Additionally, avermectin resistance in P. absoluta was inferred to be linked to behavioral resistance, a stimulus-dependent mechanism.
This comprehensive study underscores the complexity of insecticide resistance in P. absoluta, highlighting the necessity for ongoing research to develop more effective and sustainable pest management strategies for tomato production.