Analysis of insecticide resistance and transcriptome assembly of resistance associated genes in the European grapevine moth, (Lepidoptera: Tortricidae).

The European grapevine moth (Denis & Shiffermüller 1776) is an economically important pest of the vine-growing areas worldwide. Chemical insecticides have been used for its control; however, its resistance status is largely unknown in many regions. We monitored the susceptibility of several populations from Greece and Turkey.

Interaction of Whitefly Effector G4 with Tomato Proteins Impacts Whitefly Performance.

The phloem-feeding insect is an important pest, responsible for the transmission of several crop-threatening virus species. While feeding, the insect secretes a cocktail of effectors to modulate plant defense responses. Here, we present a set of proteins identified in an artificial diet on which was salivating.

Molecular diagnostics for monitoring insecticide resistance in the western flower thrips Frankliniella occidentalis.

Background: Insecticide resistance has emerged in various western flower thrips (WFT) populations across the world, threatening the efficiency of chemical control applications. Elucidation of insecticide resistance mechanisms at the molecular level provides markers for the development of diagnostics to monitor the trait and support evidence-based resistance management.

Results: TaqMan and Droplet Digital polymerase chain reaction (ddPCR) diagnostics were developed and validated, against Sanger sequencing, in individual and pooled WFT samples respectively, for the G275E mutation (nicotinic acetylcholine receptor α6 gene, nAChR α6) associated with resistance to nAChR allosteric modulators, site I (spinosyns); L1014F, T929I, T929C and T292V mutations (voltage-gated sodium channel gene, vgsc) linked with pyrethroid resistance; and I1017M (chitin synthase 1 gene, chs1) conferring resistance to growth inhibitors affecting CHS1 (benzoylureas).

Next-generation molecular diagnostics (TaqMan qPCR and ddPCR) for monitoring insecticide resistance in Bemisia tabaci.

Background: Insecticide resistance has developed in several populations of the whitefly Bemisia tabaci worldwide and threatens to compromise the efficacy of chemical control. The molecular mechanisms underpinning resistance have been characterized and markers associated with the trait have been identified, allowing the development of diagnostics for individual insects.

Results: TaqMan and Droplet Digital PCR (ddPCR) assays were developed and validated, in individual and pooled whitefly samples, respectively, for the following target-site mutations: the acetylcholinesterase (ace1) F331W mutation conferring organophosphate-resistance; the voltage-gated sodium channel (vgsc) mutations L925I and T929V conferring pyrethroid-resistance; and the acetyl-CoA carboxylase (acc) A2083V mutation conferring ketoenol-resistance.

Fungicide resistance frequencies of Botrytis cinerea greenhouse isolates and molecular detection of a novel SDHI resistance mutation.

Sensitivity of B. cinerea to commonly used fungicides against Gray mold with emphasis to the newer quinone outside inhibitor (QoIs), and succinate dehydrogenase inhibitors (SDHIs) was assessed during a monitoring survey from vegetable greenhouses in four representative regions of Crete. 42% from a total of 168 isolates were simultaneously resistant to boscalid, fluopyram, pyraclostrobin and fenhexamid but not to fludioxonil making this phenylpyrrole fungicide an excellent anti-resistance antifungal agent.

A spatiotemporal atlas of the lepidopteran pest Helicoverpa armigera midgut provides insights into nutrient processing and pH regulation.

Background: Caterpillars from the insect order Lepidoptera are some of the most widespread and destructive agricultural pests. Most of their impact is at the larval stage, where the midgut epithelium mediates the digestion and absorption of an astonishing amount of food. Although this tissue has been the subject of frequent investigation in Lepidoptera, a comprehensive expression atlas has yet to be generated.

Flupyradifurone resistance in Myzus persicae populations from peach and tobacco in Greece.

Background: Myzus persicae has evolved resistance to various insecticides in Greece. Here we examine the effectiveness of the insecticide flupyradifurone against aphid clones collected from tobacco and peach in Greece during 2017-2020. Furthermore, we monitored the frequency of the neonicotinoid resistance mutation R81T in the sampled clones, and the association between the responses to flupyradifurone and acetamiprid.

Multiple TaqMan qPCR and droplet digital PCR (ddPCR) diagnostics for pesticide resistance monitoring and management, in the major agricultural pest Tetranychus urticae.

Background: Decisions on which pesticide to use in agriculture are expected to become more difficult, as the number of available chemicals is decreasing. For Tetranychus urticae (T. urticae), a major pest for which a number of candidate markers for pesticide resistance are in place, molecular diagnostics could support decision-making for the rational use of acaricides.

Co-Expression of a Homologous Cytochrome P450 Reductase Is Required for In Vivo Validation of the CYP392A16-Based Abamectin Resistance in .

Overexpression of the cytochrome P450 monooxygenase CYP392A16 has been previously associated with abamectin resistance using transcriptional analysis in the two-spotted spider mite , an important pest species worldwide; however, this association has not been functionally validated in vivo despite the demonstrated ability of CYP392A16 to metabolize abamectin in vitro. We expressed CYP392A16 in vivo via a Gal4 transcription activator protein/Upstream Activating Sequence (GAL4/UAS) system in flies, driving expression with detoxification tissue-specific drivers. We demonstrated that CYP392A16 expression confers statistically significant abamectin resistance in toxicity bioassays in only when its homologous redox partner, cytochrome P450 reductase (TuCPR), is co-expressed in transgenic flies.

Identification and characterization of striking multiple-insecticide resistance in a Tetranychus urticae field population from Greece.

Background: Tetranychus urticae is a notorious crop pest with a worldwide distribution that has developed resistance to a wide range of acaricides. Here, we investigated the resistance levels of a T. urticae population collected from an ornamental greenhouse in Peloponnese, Greece, and analyzed its resistance mechanisms at the molecular level.

A transcriptomic and proteomic atlas of expression in the Nezara viridula (Heteroptera: Pentatomidae) midgut suggests the compartmentalization of xenobiotic metabolism and nutrient digestion.

Background: Stink bugs are an emerging threat to crop security in many parts of the globe, but there are few genetic resources available to study their physiology at a molecular level. This is especially true for tissues such as the midgut, which forms the barrier between ingested material and the inside of the body.

Results: Here, we focus on the midgut of the southern green stink bug Nezara viridula and use both transcriptomic and proteomic approaches to create an atlas of expression along the four compartments of the anterior-posterior axis.

Identification and geographical distribution of pyrethroid resistance mutations in the poultry red mite Dermanyssus gallinae.

Background: The poultry red mite (PRM) Dermanyssus gallinae is the most common ectoparasite on poultry and causes high economic losses in poultry farming worldwide. Pyrethroid acaricides have been widely used for its control and, consequently, pyrethroid resistance has arisen. In this study we aim to investigate the occurrence of resistance and study the geographical distribution of pyrethroid resistance mutations across PRM populations in Europe.

The evolution of multiple-insecticide resistance in UK populations of tomato leafminer, Tuta absoluta.

Background: The tomato leafminer, Tuta absoluta, is an economically important pest of tomatoes in Europe, Africa, Asia and South America. In the UK this species is controlled using an integrated pest management (IPM) programme which incorporates the insecticides spinosad and chlorantraniliprole. In response to UK grower concerns of loss of efficacy of these compounds at certain sites, insecticide bioassays were performed on five populations collected from four commercial glasshouses and potential mechanisms of resistance investigated.

Insecticide resistance in Trialeurodes vaporariorum populations and novel diagnostics for kdr mutations.

Background: Neonicotinoids, pyrethroids and ketoenols are currently used for the control of Trialeurodes vaporariorum (Hemiptera: Aleyrodidae). In this study, insecticide resistance status and mechanisms were investigated using classical bioassays and molecular techniques.

Results: Dose-response bioassays were performed on 19 Greek populations, among the 35 different whitefly populations used for the whole analysis.

Investigation of the contribution of RyR target-site mutations in diamide resistance by CRISPR/Cas9 genome modification in Drosophila.

Diamide insecticides are used widely against lepidopteran pests, acting as potent activators of insect Ryanodine Receptors (RyRs) and thus inducing muscle contraction and eventually death. However, resistant phenotypes have recently evolved in the field, associated with the emergence of target site resistance mutations (G4946E/V and I4790M). We investigated the frequency of the mutations found in a resistant population of Tuta absoluta from Greece (G4946V ~79% and I4790M ~21%) and the associated diamide resistance profile: there are very high levels of resistance against chlorantraniliprole (9329-fold) and flubendiamide (4969-fold), but moderate levels against cyantraniliprole (191-fold).

Molecular diagnostics for detecting pyrethroid and abamectin resistance mutations in Tetranychus urticae.

Avermectin and pyrethroid resistance mutations (the G314D and the G326E in the glutamate gated chloride channels, and the F1538I in the voltage gated sodium channel) have been reported in the spider mite Tetranychus urticae, one of the most devastating pests of protected and open field crops worldwide. We developed three TaqMan molecular diagnostic assays for monitoring the presence and frequency of these mutations in T. urticae field populations.

Ryanodine receptor point mutations confer diamide insecticide resistance in tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae).

Insect ryanodine receptors (RyR) are the molecular target-site for the recently introduced diamide insecticides. Diamides are particularly active on Lepidoptera pests, including tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae). High levels of diamide resistance were recently described in some European populations of T.

Transcription analysis of neonicotinoid resistance in Mediterranean (MED) populations of B. tabaci reveal novel cytochrome P450s, but no nAChR mutations associated with the phenotype.

Background: Bemisia tabaci is one of the most damaging agricultural pests world-wide. Although its control is based on insecticides, B. tabaci has developed resistance against almost all classes of insecticides, including neonicotinoids.