Project description:Multi-species interactions are a major force in the evolution and dynamics of ecosystems. These interactions may occur either when species affect each other directly or when they interact indirectly via an intermediary species. Direct interactions between species are best understood, but indirect interactions may also often be strong enough to alter the evolutionary trajectories of the target species. Little is known about the genetic basis of direct interactions within an ecosystem and even less data is available for indirect interactions. This experiment uses a simple model ecosystem to build a view at the transcriptome level of how interactions between plants (Arabidopsis) and rhizosphere bacteria (Pseudomonas) are altered by biotic stressors (insect herbivores) and abiotic stressors (UV-B). Keywords: stress response
Project description:Phloem-feeding pests cause extensive crop damage throughout the world yet little is understood about how plants perceive and defend themselves from these threats. The silverleaf whitefly (SLWF; Bemisia tabaci type B) is a good model for studying phloem-feeding insect-plant interactions as SLWF nymphs cause little wounding and have a long, continuous interaction with the plant. Using the Arabidopsis ATH1 GeneChip, the global responses to Silverleaf Whitefly 2nd instar feeding were examined. Keywords: stress response
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:Plants have developed a complicated resistance system, and they exhibit various defense patterns in response to different attackers. However, the determine factors of plant defense patterns are still not clear. Here, we hypothesized that damage patterns of plant attackers play an important role in determining the plant defense patterns. To test this hypothesis, we selected leafminer, which has a special feeding pattern more similar to pathogen damage than chewing insects, as our model insect, and Arabidopsis thaliana as the response plants. The local and systemic responses of Arabidopsis thaliana to leafminer feeding were investigated using the Affymetrix ATH1 genome array.
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:Multi-species interactions are a major force in the evolution and dynamics of ecosystems. These interactions may occur either when species affect each other directly or when they interact indirectly via an intermediary species. Direct interactions between species are best understood, but indirect interactions may also often be strong enough to alter the evolutionary trajectories of the target species. Little is known about the genetic basis of direct interactions within an ecosystem and even less data is available for indirect interactions. This experiment uses a simple model ecosystem to build a view at the transcriptome level of how interactions between plants (Arabidopsis) and rhizosphere bacteria (Pseudomonas) are altered by biotic stressors (insect herbivores) and abiotic stressors (UV-B). Experiment Overall Design: Arabidopsis plants were established and then split into two cohorts at 15 days. One group were innoculated with Pseudomonas aeruginosa strain 7NR and the other not. 21 days later half of each of these groups were subjected to UV-B treatment for seven days. After this period each of the four groups of plants were further subdivided and infested with aphids, caterpillars or left alone. 24 hours after infestation the plants were harvested, individuals pooled and total RNA extracted giving 12 unique conditions. Five replicates were performed in series, yielding a total of 60 samples.
Project description:Arabidopsis thaliana and Arabidopsis lyrata are two closely related Brassicaceae species, which are used as models for plant comparative biology. They differ by lifestyle, predominant mating strategy, ecological niches and genome organization. In order to explore molecular basis of specific traits, we performed RNA-sequencing of vegetative rosettes from both species. Additionally, we sequenced apical meristems and inflorescences of A. lyrata that allow for intra-specific transcriptome comparison in several major developmental stages. Please view also related dataset GSE69077 (RNA-sequencing of heat stressed A. lyrata and A. thaliana plants).