Biology subjects

Kampouraki, A.

Publications and source records attributed to Kampouraki, A..

3 recordsLinked to original sources

bioRxiv2025

Evolving resistance patterns in Tetranychus urticae and Bemisia tabaci in Greece

Pesticide resistance in agricultural pests poses a significant challenge to sustainable crop protection. In this study, we assessed the current resistance status of two key pests, Tetranychus urticae and Bemisia tabaci, in major agricultural regions of Greece. A total of 25 field populations were collected between 2023 and 2025 and tested using single-dose toxicity bioassays and droplet digital PCR (ddPCR) for known resistance-associated target-site mutations. The results revealed significant variability in susceptibility to multiple acaricides and insecticides, with several T. urticae populations displaying reduced sensitivity to abamectin, hexythiazox, and fenpyroximate. Resistance mutations such as I321T (GluCl3), I1017F (CHS1), F1538I (VGSC), and G126S (cytb) were detected at high frequencies in multiple populations, indicating multi-resistant phenotypes. In B. tabaci, widespread occurrence of F331W (ace1), L925I/T929V (VGSC), and A2083V (acc) mutations confirmed evolving resistance to organophosphates, pyrethroids, and ketoenols, respectively. Our findings underscore the ongoing evolution of resistance in these pests and highlight the need for integrated management strategies that include regular resistance monitoring and judicious pesticide use. This study provides data to guide evidence-based pest control and supports the implementation of sustainable Integrated Pest Management (IPM) practices in Greece.

pharmacology and toxicology↗

bioRxiv2022

Functional characterization of cytochrome P450s associated with pyrethroid resistance in the olive fruit fly Bactrocera oleae

Resistance to pyrethroid insecticides has evolved in Bactrocera oleae populations in Greece, threatening the efficacy of control interventions based on this insecticide class. Here we report the collection of populations from Crete with resistance levels reaching up to 331-folds, compared to susceptible laboratory strains and show that pyrethroid resistance is substantially suppressed by the PBO synergist, suggesting the involvement of detoxification enzymes. To identify specific candidate genes implicated in resistance, we performed comparative transcriptomic analysis, between the pyrethroid resistant populations from Crete and the susceptible laboratory strains, using both whole bodies and Malpighian tubules. Several genes were found differentially transcribed between resistant and susceptible flies in each comparison, with P450s being among the most highly over-expressed detoxification genes in pyrethroid resistant populations. Four of the over-expressed P450s (Cyp6A61, Cyp6G6, Cyp4P6 and Cyp6G28) were recombinantly expressed in Escherichia coli and in vitro metabolism assays revealed that CYP6A61 is capable of metabolizing alpha-cypermethrin, while CYP6G6, CYP4P6 and CYP6G28 are capable of metabolizing deltamethrin. No metabolism of neonicotinoid insecticides was recorded. We further silenced CYP6G6 in vivo, via RNAi, which led to a small, but significant increase in deltamethrin toxicity. The study provides valuable information towards the development of molecular diagnostics and evidence-based insecticide resistance management strategies.

molecular biology↗

bioRxiv2019

Functional genomics of a symbiotic community: shared traits in the olive fruit fly gut microbiota

The olive fruit fly Bactrocera oleae is a major pest of olives worldwide and houses a specialized gut microbiota dominated by the obligate symbiont \"Candidatus Erwinia dacicola\". Ca. E. dacicola is thought to supplement dietary nitrogen to the host, with only indirect evidence for this hypothesis so far. Here, we sought to investigate the contribution of the symbiosis to insect fitness and explore the ecology of the insect gut. For this purpose, we examined the composition of bacterial communities associated with Cretan olive fruit fly populations, and inspected several genome and transcriptome assemblies. We identified, and reconstructed the genome of, a novel component of the gut microbiota, Tatumella sp. TA1, which is stably associated with Mediterranean olive fruit fly populations. We also reconstructed a number of pathways related to nitrogen assimilation and interaction with the host. The results show that, despite variation in taxa composition of the gut microbial community, core functions related to the symbiosis are maintained. Functional redundancy between different microbial taxa was observed for genes allowing urea hydrolysis. The latter is encoded in the obligate symbiont genome by a conserved urease operon, likely acquired by horizontal gene transfer, based on phylogenetic evidence. A potential underlying mechanism is the action of mobile elements, especially abundant in the Ca. E. dacicola genome. This finding, along with the identification, in the studied genomes, of extracellular surface structure components that may mediate interactions within the gut community, suggest that ongoing and past genetic exchanges between microbes may have shaped the symbiosis.

evolutionary biology↗