Project description:In this study, we profiled the transcriptional changes in a polyphagous spider mite, Tetranychus urticae, after adaptation to spatial and tempospatial stress. We show heritable down-regulation of genes encoding for core enzymes involved in the citric acid and gluconeogenesis/glycolyse pathways (glucose 6-phosphatase among others). Additionally, we observe heritable transcriptional changes in amino acid pathways (methionine, tyrosine and phenylalanine) and in laterally acquired genes from bacteria (cobalamin-independent methionine synthase). By similiar study results in other organisms, we argue that these heritable transcriptional changes (partially) underpin the changed life history traits observed in our experimental evolution set-up.
Project description:Generalist arthropod herbivores rapidly adapt to a broad range of host plants. However, the extent of transcriptional reprogramming in the herbivore and its hosts associated with adaptation remains poorly understood. Using the spider mite Tetranychus urticae and tomato as models with available genomic resources, we investigated the reciprocal genome-wide transcriptional changes in both spider mite and tomato as a consequence of mite’s adaptation to tomato We used microarray to assess global gene expression in Solanum lycopersicum cv. Moneymaker upon Tetranychus urticae attack by tomato-adapted and non-adapted spider mite lines.
Project description:While pathogen-induced immunity is comparatively well characterized, far less is known about plant defense responses to arthropod herbivores. To date, most molecular-genetic studies of plant-arthropod interactions have focused on insects. However, plant-feeding (phytophagous) mites are also pests of diverse plants, and mites induce different patterns of damage to plant tissues than do well-studied insects (e.g., Lepidopteran larvae or aphids). The two-spotted spider mite, Tetranychus urticae, is among the most significant mite pests in agriculture. T. urticae is an extreme generalist that has been documented on a staggering number of plant hosts (more than 1,100), and is renowned for the rapid evolution of pesticide resistance. To understand reciprocal interactions between T. urticae and a plant host at the molecular level, we examined mite herbivory using Arabidopsis thaliana. Despite differences in feeding guilds, we found that transcriptional responses of A. thaliana to mite herbivory generally resembled those observed for insect herbivores. In particular, defense to mites was mediated by jasmonic acid (JA) biosynthesis and signaling. Further, indole glucosinolates dramatically increased mite mortality and development times. Variation in both basal and activated levels of these defense pathways might also explain differences in mite damage and feeding success between A. thaliana accessions. On the herbivore side, a diverse set of genes associated with detoxification of xenobiotics was induced upon exposure to increasing levels of in planta indole glucosinolates. Our findings provide molecular insights into the nature of, and response to, herbivory for a representative of a major class of arthropod herbivores. We used microarray to assess global gene expresion in Arabidopsis thaliana upon Tetranychus urticae attack in two A. thaliana accessions: Bla-2, resistant to spider mite herbivory and Kon, susceptible to spider mite herbivory.
Project description:While pathogen-induced immunity is comparatively well characterized, far less is known about plant defense responses to arthropod herbivores. To date, most molecular-genetic studies of plant-arthropod interactions have focused on insects. However, plant-feeding (phytophagous) mites are also pests of diverse plants, and mites induce different patterns of damage to plant tissues than do well-studied insects (e.g., Lepidopteran larvae or aphids). The two-spotted spider mite, Tetranychus urticae, is among the most significant mite pests in agriculture. T. urticae is an extreme generalist that has been documented on a staggering number of plant hosts (more than 1,100), and is renowned for the rapid evolution of pesticide resistance. To understand reciprocal interactions between T. urticae and a plant host at the molecular level, we examined mite herbivory using Arabidopsis thaliana. Despite differences in feeding guilds, we found that transcriptional responses of A. thaliana to mite herbivory generally resembled those observed for insect herbivores. In particular, defense to mites was mediated by jasmonic acid (JA) biosynthesis and signaling. Further, indole glucosinolates dramatically increased mite mortality and development times. Variation in both basal and activated levels of these defense pathways might also explain differences in mite damage and feeding success between A. thaliana accessions. On the herbivore side, a diverse set of genes associated with detoxification of xenobiotics was induced upon exposure to increasing levels of in planta indole glucosinolates. Our findings provide molecular insights into the nature of, and response to, herbivory for a representative of a major class of arthropod herbivores. We used microarray to assess global gene expresion in Arabidopsis thaliana upon Tetranychus urticae attack in two A. thaliana accessions: Bla-2, resistant to spider mite herbivory and Kon, susceptible to spider mite herbivory. 3 week old Arabidopsis thaliana plants were subjected to Tetranychus urticae attack through application of 10 mites for various periods of time (timecourse scenario) or hundreds of mites for 1 hour (feeding site scenario).
Project description:The two-spotted spider mite Tetranychus urticae is an extreme polyphaguous crop pest. Next to an increased detoxification potential of plant secondary metabolites, it has recently been shown that spider mites manipulate plant defences. Salivary constituents are proposed to play an important role during the interaction with its many hosts. The proteomic composition of saliva delivered into artificial diet by spider mites adapted to various hosts - bean, soy, maize, tomato -was determined using Orbitrap mass spectrometry. Over 200 different proteins were identified, many of unknown function and in numerous cases belonging to multi-membered gene families. A selection of these putative salivary proteins was validated using whole-mount in situ hybridizations and expression was shown to be localized in the anterior and dorsal podocephalic glands of the spider mite. Host-plant dependent expression was evident from the proteomics dataset and was further studied in detail by micro-array based genome wide gene expression profiling of mites maintained on the host plants under study. Previously obtained gene-expression datasets were further used to get more insight in the expression profile over different life stages and physiological states. To conclude, for the first time the T. urticae salivary proteome repertoire was characterized using a custom feeding hemisphere-based enrichment technique. This knowledge will assist in unraveling the molecular interactions between phytophagous mites and their host plants. This may ultimately facilitate the development of mite-resistant crops.
Project description:The extreme generalist two-spotted spider mite, Tetranychus urticae, which is documented to feed on more than 1100 plant hosts, is becoming an increasingly important agricultural pest. Historically, as studies of plant-herbivore interactions have focused largely on insects, considerably less research has investigated plant responses to spider mite herbivores, especially in grasses. To identify intraspecific differences in maize response to T. urticae, we collected RNA-seq data from three maize (Zea mays) inbred lines (B73, B75 and B49) as well as two F1 lines arising from crosses between B73 x B75 and B73 x B96. For each maize line, RNA-seq data was collected from uninfested leaves (control) and leaves infested with T. urticae for 24 hours.
Project description:Spider mites, including the two-spotted spider mite (Tetranychus urticae, TSSM) and the Banks grass mite (Oligonychus pratensis, BGM), are becoming increasingly important agricultural pests. The TSSM is an extreme generalist documented to feed on more than 1100 plant hosts. In contrast, the BGM is a grass specialist, with hosts including important cereal crops like maize, wheat, sorghum and barley. Historically, studies of plant-herbivore interactions have focused largely on insects. However, far less is known about plant responses to spider mite herbivores, especially in grasses, and whether responses differ between generalists and specialists. To identify plant defense pathways responding to spider mites, we collected time course RNA-seq data from barley (Hordeum vulgare L.) infested with TSSMs and BGMs. Additionally, and as a comparison to the physical damage caused by spider mite feeding, a wounding treatment was also included. The experiment was performed with four biological replicates across each of the following (28 samples in total): no infestation (C, control), 2hr after wounding (W2), 24hr after wounding (W24), 2hr after TSSM infestation (T2), 24hr after TSSM infestation (T24), 2hr after BGM infestation (B2), and 24hr after BGM infestation (B24).