Project description:The red spider mite, Tetranychus evansi, is a oligophagous specialist mite pest of Solanaceae plants. Here, we described tomato transcriptional responses to T. evansi feeding and compared them to responses to tomato-adapted and -non-adapted strains of generalist herbivorous spider mite Tetranychus urticae. We used microarray to assess global gene expression in Solanum lycopersicum cv. Heinz 1706 upon T. evansi attack.
Project description:This SuperSeries is composed of the following subset Series: GSE31525: Spider mite preliminary feeding experiment with mites reared on bean and two Arabidopsis thaliana accessions GSE31527: Developmental stage-specific gene expression in the two-spotted spider mite (Tetranychus urticae) GSE32005: Developmental stage-specific small RNA composition in the two-spotted spider mite (Tetranychus urticae) GSE32009: Transcriptional responses of the two-spotted spider mite (Tetranychus urticae) after transfer to different plant hosts Refer to individual Series
Project description:Tomato plants are commonly attacked by herbivorous mites, including by generalist Tetranychus urticae and specialists Tetranychus evansi and Aculops lycopersici. Mite feeding induces plant defense responses that reduce mite performance. However, via poorly understood mechanisms, T. evansi and A. lycopersici suppress plant defenses and, consequently, maintain a high performance on tomato. Accordingly, on a shared host, non-adapted T. urticae can be facilitated by either of the specialist mites, likely via the suppression of plant defenses. To better understand defense suppression and indirect plant-mediated interactions between herbivorous mites, we used microarrays to analyze transcriptomic changes in tomato after attack by either a single mite species (T. urticae, T. evansi, A. lycopersici) or two species simultaneously (T. urticae plus T. evansi or T. urticae plus A. lycopersici). Additionally, we assessed mite-induced changes in defense-associated phytohormones using LC-MS/MS. Compared to non-infested controls, jasmonates (JAs) and salicylate (SA) accumulated to higher amounts upon all mite-infestation treatments, but lowest increases were detected after single infestations with defense-suppressors. Strikingly, whereas 8 to 10% of tomato genes was differentially expressed upon single infestations with T. urticae or A. lycopersici, only 0.1% was altered in T. evansi-infested plants. Transcriptome analysis of dual-infested leaves revealed that T. evansi dampened T. urticae-triggered host responses on a genome-wide scale, while A. lycopersici primarily suppressed T. urticae-induced JA defenses. Our results provide valuable new insights into the mechanisms underlying host defense suppression and the plant-mediated facilitation of competing herbivores.
Project description:We sequenced messenger RNA from mixed stages of the two-spotted spider mite (Tetranychus urticae) reared on bean (Phaseolus vulgaris cv California Red Kidney; the laboratory host plant for mites) and two Arabidopsis thaliana accessions which were considered to either be susceptible (Kondara) or resistant (Bla-2) to mite feeding. This pilot experiment was conducted to assess gene expression differences of mites grown on sensitive versus resistant Arabidopsis accessions, as well as differences in mites feeding on different host species. The expression data was used for gene model validation of genes predicted by EuGene in the spider mite genome and to assess gene expression levels. Examination of gene expression of spider mites reared on beans and two Arabidopsis accessions (Kondara and Bla-2).
Project description:The two-spotted spider mite, Tetranychus urticae, is one of the most significant mite pests in agriculture that can feed on more than 1,100 plant hosts, including model plants Arabidopsis thaliana and tomato, Solanum lycopersicum. Here, we described tomato transcriptional responses to spider mite feeding and compared them to Arabidopsis in order to determine conserved and divergent responses to this pest. 2,133 differentially expressed genes (DEGs) were detected at 1, 3, 6, 12 or 24 hours post spider mite infestation (hpi) relative to non-infested control plants. Based on Biological Process Gene Ontology annotations, improved in the course of our analysis, DEGs were grouped in 60 significantly enriched gene sets that highlighted perception of the spider mite attack (1 hpi), metabolic reprogramming (3-6 hpi), and establishment and maintenance of the defense responses (6-24 hpi). We used microarray to assess global gene expression in Solanum lycopersicum cv. Heinz 1706 upon Tetranychus urticae attack. 1 month old tomato plants were subjected to Tetranychus urticae attack through application of 100 adult mites on a terminal leaflet of leaf 3 for various periods of time (timecourse scenario) or hundreds of mites for 1 hour (feeding site scenario).
Project description:Genome annotation of the chelicerate Tetranychus urticae revealed the absence of many canonical immunity genes. T. urticae either does not mount an immune response or it induces uncharacterized immune pathways. To disentangle these two hypotheses, we performed transcriptomic analysis of mites injected with bacteria vs mites injected with LB-buffer. Two types of bacteria were injected: E. coli and B. megaterium and transcriptomes were sampled 3, 6 and 12 hrs after injection. We found no consistent differential expression after bacterial infection, supporting the hypothesis that spider mites do not mount an immune response. We hypothesize that the apparent absence of inducable immunity pathways in T. urticae is a result of relaxed selective pressure due to ecological factors.
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: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, and sorghum. Historically, studies of plant-herbivore interactions have focused largely on insects. As such, far less is known about plant responses to spider mite herbivores, especially in grasses, and whether responses differ between generalist and specialist mites. To identify plant defense pathways responding to spider mites, we collected time course RNA-seq data from maize (Zea mays) 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. In total, four biological samples were generated per treatment.
Project description:We sequenced messenger RNA from mixed stages of the two-spotted spider mite (Tetranychus urticae) reared on bean (Phaseolus vulgaris cv California Red Kidney; the laboratory host plant for mites) and two Arabidopsis thaliana accessions which were considered to either be susceptible (Kondara) or resistant (Bla-2) to mite feeding. This pilot experiment was conducted to assess gene expression differences of mites grown on sensitive versus resistant Arabidopsis accessions, as well as differences in mites feeding on different host species. The expression data was used for gene model validation of genes predicted by EuGene in the spider mite genome and to assess gene expression levels.