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: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. In order to refine the involvement of jasmonic acid (JA) in mite-induced responses, we analyzed transcriptional changes in tomato JA signaling mutant defenseless1 (def-1) upon JA treatment and spider mite herbivory. We used microarray to assess global gene expression in Solanum lycopersicum def-1 cv. Castlemart upon jasmonic acid treatment and Tetranychus urticae attack. 1 month old def-1 tomato plants were subjected to Tetranychus urticae attack through application of 100 adult mites on a terminal leaflet of leaf 3 for 24 h or plants were sprayed with 1 mM jasmonic acid solution.
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:Recently, we elucidated T. urticae’s repertoire of secreted salivary proteins, revealing several members of expanded protein families with unknown functions [PMID: 27703040]. In this study, mite salivary secretions were additionally examined using a peptidomics approach.
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).
Project description:The goal of our microarray experiments was to compare the gene expression profile of two spirodiclofen resistant spider mite strains (SR-VP and SR-TK) with that of a susceptible spider mite strain (LS-VL) 5 samples were analyzed: 3 biological replicates for SR-VP, 2 biological replicates for SR-TK
Project description:Drought and herbivores are main threats to crop production. Barley plants were subjected to dehydration, spider mite attack or to a combination of both stresses. RNA-seq analyses were done to know how individual and double abiotic-biotic stresses promote changes in the transcriptome.
Project description:Our goal was to investigate the transcriptional response of T. urticae to different Arabidopsis plants with varying levels of indole glucosinolates. Bean is the ancestral host plant for the T. urticae strain used in this study. Adult female spider mites were transferred to the three Arabidopsis lines (Col-0, qKo, atr1D) or bean, and after 24 hours, the gene expression levels were analyzed. 12 samples were investigated; 4 biological replicates for three comparisons: QKO (qKo vs. Col-0), ATR1D (atr1D vs. Col-0), and COL-0 (Col-0 vs. bean).
Project description:To gain novel molecular insights into quantitative late blight resistance, we performed a high-resolution quantitative analysis of gene expression using potato cultivars with contrasting SNP alleles at the StAOS2 locus associated with maturity corrected resistance (MCR). SuperSAGE samples were generated from uninfected and infected plants of the selected genotypes under controlled environmental conditions. Genotypes were pooled to reduce the influence of the genetic background on the transcriptome. Nine SuperSAGE samples were prepared from artificially inoculated plants in a growth chamber using total RNA of the pooled 14, 6 and 9 genotypes in groups A1, A2 and B2, respectively, at three infection time points T0, T1 and T2. Combining the tag counts of both NlaIII and DpnII libraries resulted in 1.1 to 6.2 million tags per sample. Of total 266361 unique tags (unitags), 52.6% matched to the potato genome sequence when up to three mismatches per 26 base pairs were allowed, and 23.3% matched without mismatch. Fifteen pair wise comparisons were performed between the nine SuperSAGE samples to identify transcripts that were differentially expressed in response to infection (six comparisons) or between three genotype pools at the infection time points T0, T1 and T2 (nine comparisons). The number of unitags per comparison ranged from 127 000 to 182 000 (average 158 000). Between 2100 and 11800 tags were differentially expressed in pair wise comparisons, depending on arbitrary cut-off p-values for a significant difference. The highest number of differences was observed for the comparison between genotype pools A1 and A2 one day after infection (A1-T1 vs A2-T1), and the lowest between genotype pools A2 and B2 two days after infection (B2-T2 vs A2-T2). The number of differences in response to infection and between genotype pools even before infection (T0) was in the same order of magnitude. Based on the annotations in the DFCI potato gene index, in the potato genome and in few cases by BLASTX searches against the protein database at NCBI, transcripts that showed reproducible differential expression over the infection time course or between genotype pools A1, A2 and B2 were grouped in 16 functional categories, with overlaps between categories. Genes with genotype dependent, constitutive differential expression provide excellent targets for developing novel diagnostic markers for breeding cultivars with improved quantitative resistance to late blight and possibly other biotic and abiotic stresses. Relevant in this respect appear, besides numerous genes of unknown or ill-defined function, genes with known function involved in stress responses, photosynthesis, protein biosynthesis, protein degradation via the 26S proteasome, transport of proteins, lipids, ions and other small molecules, cell wall structure and many others. Eighteen SuperSAGE libraries were constructed based on nine leaf samples from one infection experiment. For each time point (T0, T1 and T2) one leaflet each of 14, 6 and 9 SL genotypes in genotypic groups A1, A2 and B2, respectively, were pooled. Frozen pooled leaf tissue was powdered in a CryoMill. SuperSAGE libraries were generated at GenXPro GmbH (Frankfurt, Germany) essentially as described (Matsumura et al. 2010). To prevent amplification biases the TrueQuant technology was applied as described by B. Rotter (Patent application Nr. WO2009152928). Besides NlaIII (recognition site: 5M-bM-^@M-^Y-CATG-3M-bM-^@M-^Y), DpnII (recognition site: 5M-bM-^@M-^Y-GATC-3M-bM-^@M-^Y) was used as second anchoring enzyme, to capture transcripts without a NlaIII site. Therefore, the 26 bp tags carry either CATG or GATC at their 5M-bM-^@M-^Y end. The libraries were pooled and sequenced by Solexa/Illumina technology (Illumina, Inc., USA).