Life Sciences Commons^™

Characterization Of Etoxazole Resistance In Tetranychus Urticae Populations Collected From Commercial Greenhouses & Fields In Ontario, Jeremy Spenler

Electronic Thesis and Dissertation Repository

In this investigation, etoxazole resistance was monitored in two spotted spider mite (TSSM) populations collected from commercial greenhouses in Ontario. The frequency of an etoxazole resistant, recessive target-site mutation, I1017F, in chitin synthase I (CHS1) was tracked within populations over the course of the study. Cytochrome P450 (P450) activity emerged as a possible alternative mechanism to resist etoxazole exposure in one population.

Using genetic crossing between highly resistant mite populations and a susceptible lab population, filial (F1) hybrid populations were created. The recessive I1017F target-site mutation was abolished in F1 hybrids highly susceptible to etoxazole, while elevated P450 …

Development Of Reverse Genetics Tools In The Two-Spotted Spider Mite Tetranychus Urticae, Nivitha Bhaskar

Electronic Thesis and Dissertation Repository

Tetranychus urticae, commonly known as the two-spotted spider mite, poses a significant threat to agriculture due to its ability to feed on a diverse range of plant hosts and its strong detoxification abilities in overcoming xenobiotic response. With global warming projected to increase spider mite infestations, it is vital to study the detoxification genes that enable the mite to adapt and survive. The spider mite genome sequence reveals a unique set of detoxification genes that can be studied using RNAi as a promising reverse genetic tool. However, the current genetic toolkit requires improvement. This study examined the effectiveness of …

My Summer Working With Two-Spotted Spider Mites, Renée A. Smith

Undergraduate Student Research Internships Conference

Two-spotted spider mites are a polyphagous pest, capable of eating a magnitude of food crops which causes a large problem for Canadian agriculture. Their ability to consume various crops stems from their ability to adapt to various chemical defence mechanisms. This ability allows them to acquire resistance to many commonly used pesticides. This has resulted in large infections in Canadian farms with few options to prevent the pests from affecting crop yields. Take a look at my project if you'd like to see how the Grbic lab is working to combat this issue using genetic engineering techniques!

Establishment Of A Pesticide Resistance Monitoring Tool For The Two-Spotted Spider Mite, Tetranychus Urticae, Hanna Varonina

Electronic Thesis and Dissertation Repository

Two-spotted spider mite (TSSM), or Tetranychus urticae (Koch), is a major agriculture pest known for its rapid development of resistance to pesticides. The analysis of spider mites’ pesticide resistance demonstrated that resistance patterns and frequencies vary between T. urticae strains collected from different geographic locations and host plants. This research aims at characterization of pesticide resistance patterns in mite populations present in greenhouses in the Southwestern Ontario by identifying genetic and metabolic markers of their pesticide resistance. The establishment of these markers lays the basis for development of a pesticide resistance diagnostic tool that will enable prediction of population resistance …

Functional Characterization Of Vesicular Trafficking Genes In The Midgut Of Tetranychus Urticae Via Rna Interference, Sean Pham

Electronic Thesis and Dissertation Repository

The two-spotted spider mite Tetranychus urticae is a polyphagous agricultural pest of economic importance. Previous studies have established that reduced gene expression of COPB2, SNAP-α, and V-ATPase genes with RNAi and lowers both the survivorship and fecundity of T. urticae. A visible phenotype was also associated with changes to the digestive cells of the midgut after treatment. Serial sections of paraffin embedded RNAi treated mites to determine the changes caused by the transcriptional silencing of the three focal genes. COPB2 silencing leads to a significant increase in the number of juvenile digestive cells, while SNAP-α and V-ATPase …

The Role Of V-Atpase In Regulating Ph In The Digestive Tract Of Tetranychus Urticae Koch, Zoran Culo

Electronic Thesis and Dissertation Repository

The phytophagous two-spotted spider mite, Tetranychus urticae (Koch), is a major global pest to agriculture and other plant-production industries. Digestive tract pH is a key factor in regulating the enzymatic activity that facilitates digestion and detoxification of ingested plant cell contents and in my thesis I used various pH indicator dyes to determine the pH of regions of the digestive tract in T. urticae, in vivo. Digital colour values of stained specimen images were cross-referenced with the colour values from images of each dye taken at different pH values to determine the digestive tract pH in non-fed, fed …

Tetranychus Urticae Adaptation To Tomato, Kristie A. Bruinsma

Electronic Thesis and Dissertation Repository

The arms race between plants and herbivores has resulted in a great diversity of plant compounds to act as defences against attackers. It has concurrently resulted in herbivorous pest adaptations to host defences, including plant-host defence suppression through the action of secreted effectors, and detoxification of phytochemicals ingested during feeding. While these two mechanisms of herbivore adaptation are relatively well studied, they have not been tested for use at the same time. This study uses the model plant species Solanum lycopersicum (tomato), and the model arthropod species Tetranychus urticae (two-spotted spider mite), to characterize the utilization of the above-mentioned mechanisms …

Adaptation Mechanisms Of Two-Spotted Spider Mite, Tetranychus Urticae, To Arabidopsis Indole Glucosinolates, Golnaz Salehipourshirazi

Electronic Thesis and Dissertation Repository

The two-spotted spider mite Tetranychus urticae Koch is a key agricultural pest that causes significant yield losses in a wide range of economically important crops. Rapid development of resistance to several classes of pesticides in T. urticae necessitates introduction of alternative management strategies to control this pest. Indole glucosinolates (IGs) are secondary metabolites found in Brassicaceae plants (including Arabidopsis thaliana) that have been shown to be effective against T. urticae and could be potential candidates to control spider mites. However, a laboratory population selected on IG-containing Arabidopsis was able to evolve adaptation to this plant. The overall objective of …

Characterization Of Acaricide Resistance, Plant-Mediated Rnai Against Two-Spotted Spider Mites (Tetranychus Urticae Koch), And Assessing Off- And Non-Target Effects, Hooman Hosseinzadeh Namin

Electronic Thesis and Dissertation Repository

The two-spotted spider mite (TSSM), Tetranychus urticae (Koch), is one of the most damaging agricultural pests in the world. It feeds on over 150 crops, causing considerable yield losses in greenhouses and agricultural fields. Currently, using synthetic acaricides is the main method to control TSSM. However, it can develop resistance to acaricides with repeated exposure, and typically resistance can occur within two to four years. To understand the underlying mechanisms of spider mite adaptation to acaricides is an essential part of resistance management strategy. The resistance ratio of the pyridaben-selected strain compared with the pre-selection strain was estimated at greater …

Tomato Whole Genome Transcriptional Response To Tetranychus Urticae Identifies Divergence Of Spider Mite-Induced Responses Between Tomato And Arabidopsis, Catherine Martel, Vladimir Zhurov, Marie Navarro, Manuel Martinez, Marc Cazaux, Philippe Auger, Alain Migeon, M. Estrella Santamaria, Nicky Wybouw, Isabel Diaz, Thomas Van Leeuwen, Maria Navajas, Miodrag Grbic, Vojislava Grbic

Biology Publications

The two-spotted spider mite Tetranychus urticae is one of the most significant mite pests in agriculture, feeding on more than 1,100 plant hosts, including model plants Arabidopsis thaliana and tomato, Solanum lycopersicum. Here, we describe timecourse tomato transcriptional responses to spider mite feeding and compare them with Arabidopsis in order to determine conserved and divergent defense responses to this pest. To refine the involvement of jasmonic acid (JA) in mite-induced responses and to improve tomato Gene Ontology annotations, we analyzed transcriptional changes in the tomato JA-signaling mutant defenseless1 (def-1) upon JA treatment and spider mite herbivory. Overlay …

Two Spotted Spider Mite (Tetranychus Urticae) Selection To Arabidopsis Thaliana, Huzefa Ratlamwala

Electronic Thesis and Dissertation Repository

Spider mite feeding on A. thaliana induces the production of indole glucosinolates (IGs), plant secondary metabolites that negatively affect mite performance. In this study I conducted selection experiments on A. thaliana with varying levels of IGs, to determine if mites could adapt to IGs and other defense compounds. After 12 months, mites reared on host with IGs performed significantly better on A. thaliana than mites maintained on beans. However, an adaptation cost was detected between selected mite lines and their ancestral host. The qRT-PCR data on different mite lines revealed that the detoxification genes previously identified may only be involved …

Arabidopsis Thaliana-Spider Mite Interaction: Plant Perception, Signalling, And Response, Kristie A. Bruinsma

Electronic Thesis and Dissertation Repository

The two-spotted spider mite, Tetranychus urticae, is a cell-content feeding chelicerate herbivore, feeding on over 1000 plant species, one of which is Arabidopsis thaliana. This research uses microarray data from two A. thaliana accessions that differ in susceptibility to spider mite feeding to identify how the plant defends itself against this herbivore. Mutant analysis of induced plant defense pathways and physiological assays of mite performance indicate that A. thaliana utilizes: a) damage associated molecular pattern receptors, PEPR1 and PEPR2, to aid in perception of attack; b) jasmonic acid as the key phytohormone involved in resistance signalling; and c) …