Project description:Rice, the world’s most important food crop, is attacked by multiple herbivores and pathogens.the rice striped stem borer (SSB) Chilo suppressalis is one of another most important rice insect pests. Here, we use Affymetrix Whole-Genome rice arrays to detect SSB infestation responsive genes.
Project description:Priming of plant defenses provides increased plant protection against herbivores and reduces the allocation costs of defense. Defense priming in woody plants remains obscure, in particular due to plant development traits such as the endogenous rhythmic growth displayed by oaks (Quercus robur). By using bioassays with oak microcuttings, and by combining transcriptomic and metabolomic analyses, we investigated how leaf herbivory by Lymantria dispar and root inoculation with the ectomycorrhizal fungus Piloderma croceum prime oak defenses. We further investigated how defense priming is modulated by rhythmic growth of the oaks. A first herbivory challenge in oak leaves primed newly grown leaves for an enhanced induction of jamonic acid (JA)-related direct defenses, or enhanced emission of volatiles, depending on the specific growth stage at which the plants where challenged. Root inoculation with Piloderma abolished the enhanced induction of JA-related defenses and volatile emission. Our results indicate that a first herbivore attack primes direct and indirect defenses of newly formed oak leaves, and that the specific display of defense priming is modulated by rhythmic growth. Our results further show that the priming memory in oaks can be transmitted to the next growth cycle even to the leaves of the new shoot unit.
Project description:Arabidopsis thaliana plants were infested i) with sucking insect herbivores (the generalist aphid Myzus persicae and the specialist aphid Brevicoryne brassicae), ii) with chewing insect herbivores (generalist caterpillars of Spodoptera exigua and specialist caterpillars of Pieris rapae) or iii) were treated by wounding. For each treatment, rosette leaves were harvested at two time points (6h and 24h) after removal of insects. For chewing herbivores and wounding both local, i.e. immediately damaged leaves, and systemic, i.e. undamaged leaves from the same plant, were collected. Control plants were uninfested, but otherwise equally treated and harvested in parallel. We tested the hypothesis that Arabidopsis can recognize and respond differentially to insect species at the transcriptional level using a genome wide microarray. Transcriptional reprogramming was characterized using co-expression analysis in damaged and undamaged leaves at two times in response to mechanical wounding and four insect species. In all, 2778 (10.6%) of annotated genes on the array were differentially expressed in at least one treatment. Responses differed mainly between aphid and caterpillar and sampling times. Responses to aphids and caterpillars shared only 10% of up-regulated and 8% of down-regulated genes. Responses to two caterpillars shared 21% and 12% of up- and down-regulated genes, whereas responses to the two aphids shared only 7% and 4% of up-regulated and down-regulated genes. Overlap in genes expressed between 6h and 24h was 3-15%, and depended on the insect species. Responses in attacked and unattacked leaves differed at 6h but converged by 24h. Genes responding to the insects are also responsive to many stressors and included primary metabolism. Aphids down-regulated amino acid catabolism; caterpillars stimulated production of amino acids involved in glucosinolate synthesis. Co-expression analysis revealed 17 response networks. Transcription factors were a major portion of differentially expressed genes throughout and responsive genes shared most of the known or postulated binding sites.
Project description:The aim of this experiment was to compare the transciptome of the fall armyworm (Spodoptera frugiperda) strain SUS (a laboratory insecticide-susceptible standard) with organophosphate (OP) and pyrethroid (PYR) resistant strains were collected in cornfields located in Minas Gerais and Mato Grosso States, Brazil, in 2008 and maintained in the laboratory under selection with chlorpyrifos (at increasing discriminating doses from 100 up to 400 µg of insecticide/g of insect in a topical bioassay) or lambda-cyhalothrin (from 8.4 up to 27 µg of insecticide/g of insect) respectively The custom microarray used in this study was designed using the Agilent eArray platform (Agilent Technologies). A SurePrint HD (8×15k) expression array was designed using the base composition and the best probe methodologies to design sense orientation 60-mer probes with a 3′ bias. The FAW EST database (SPODOBASE) was used as the reference transcriptome (Negre, Hotelier et al. 2006). These sequences are derived from 8 cDNA libraries as follows: Sf1F: Fat body, Sf1H: Hemocyte, Sf1M: Midgut, Sf1P: Pool of various tissues, Sf2H: Immune Challenged hemocytes, Sf2L: Sf21 Cell lines sequences, Sf2M: Xenobiotic Induced Midgut and Sf9L: Sf9 cell lines sequences. All assembled contigs and singlets were kindly sent by the website maintainers. The BLAST2GO software v.2.3.1 (http://www.blast2go.org) was used to annotate the EST database. 60-mer probes were designed for all 7,552 assembled contigs and 5,519 annotated singlets (BlastX), totaling 13,071 sequences. For contigs encoding detoxification enzymes (P450s, GSTs and CEs) three probes were designed. Additional probe groups for 15 control genes were also included. For reference all sequences are included in the zip file with array data. References: Negre, V., T. Hotelier, et al. (2006). "SPODOBASE : an EST database for the lepidopteran crop pest Spodoptera." BMC Bioinformatics 7: 322.
Project description:RNA-seq was used to study the genes expressed in peculiar glandular organs that transiently appear in insect embryos and are called the pleuropodia. The locust Schistocerca gregaria (Orthoptera) was used as a model. The purpose of the study is to identify the function of these organs. Our results suport the hypothesis (Slifer, 1937) that the pleuropodia secrete enzymes that digest the serosal cuticle before hatching. Additionally, we found that the pleuropodia may also have other functions, such as in embryonic immunity. The pleuropodia are peculiarly modified limbs. We show that in their early stages both legs and pleuropodia share a similar genetic landscape, but as the appendages become more morphologically diverse they became also more diverse genetically.
Project description:High temperature events can disrupt species interactions, including those among hosts, symbionts, and natural enemies. Understanding the genetic and physiological processes underlying these disruptions is a critical scientific challenge in this era of anthropogenic climate change. We explore how high temperatures disrupt the interactions among an herbivorous insect host, Manduca sexta, its insect parasitoid, Cotesia congregata, and the parasitoid’s symbiotic virus. In this system, high temperatures kill developing parasitoids, but not hosts. We evaluated the physiological and transcriptomic causes of thermal mismatch in ecological interactions using parasitoid egg in vitro experiments, immunological assays, and RNAseq. We found that high temperatures disrupt the capacity of the parasitoid’s symbiotic virus to immunosuppress the host insect, resulting in thermal mismatch and death of the parasitoid. At the transcriptomic level, key viral genes involved in suppressing host immune pathways showed reduced expression, driven by the virus’s circular genomic structure. This work is among the first to demonstrate the genetic and physiological mechanisms by which a symbiont limits the ecological functioning of host-parasite dynamics, and provides a framework for understanding how molecular processes give rise to ecological outcomes in response to high temperature events caused by climate change.
Project description:Rice, the worldM-bM-^@M-^Ys most important food crop, is attacked by multiple herbivores and pathogens.the rice striped stem borer (SSB) Chilo suppressalis is one of another most important rice insect pests. Here, we use Affymetrix Whole-Genome rice arrays to detect SSB infestation responsive genes. RNA samples from five damaged stems of SSB-challenged 24 h rice plants or five stems from unchallenged plants (for control samples) were used to array analysis. Two replicate biological experiments of SSB treatment rice arrays and one control samples array were peformed.
Project description:The aim of this experiment was to compare the transciptome of the fall armyworm (Spodoptera frugiperda) strain SUS (a laboratory insecticide-susceptible standard) with organophosphate (OP) and pyrethroid (PYR) resistant strains were collected in cornfields located in Minas Gerais and Mato Grosso States, Brazil, in 2008 and maintained in the laboratory under selection with chlorpyrifos (at increasing discriminating doses from 100 up to 400 M-BM-5g of insecticide/g of insect in a topical bioassay) or lambda-cyhalothrin (from 8.4 up to 27 M-BM-5g of insecticide/g of insect) respectively The custom microarray used in this study was designed using the Agilent eArray platform (Agilent Technologies). A SurePrint HD (8M-CM-^W15k) expression array was designed using the base composition and the best probe methodologies to design sense orientation 60-mer probes with a 3M-bM-^@M-2 bias. The FAW EST database (SPODOBASE) was used as the reference transcriptome (Negre, Hotelier et al. 2006). These sequences are derived from 8 cDNA libraries as follows: Sf1F: Fat body, Sf1H: Hemocyte, Sf1M: Midgut, Sf1P: Pool of various tissues, Sf2H: Immune Challenged hemocytes, Sf2L: Sf21 Cell lines sequences, Sf2M: Xenobiotic Induced Midgut and Sf9L: Sf9 cell lines sequences. All assembled contigs and singlets were kindly sent by the website maintainers. The BLAST2GO software v.2.3.1 (http://www.blast2go.org) was used to annotate the EST database. 60-mer probes were designed for all 7,552 assembled contigs and 5,519 annotated singlets (BlastX), totaling 13,071 sequences. For contigs encoding detoxification enzymes (P450s, GSTs and CEs) three probes were designed. Additional probe groups for 15 control genes were also included. For reference all sequences are included in the zip file with array data. References: Negre, V., T. Hotelier, et al. (2006). "SPODOBASE : an EST database for the lepidopteran crop pest Spodoptera." BMC Bioinformatics 7: 322. Two-condition experiment. Slide 1: SUS vs. OP S. fugiperda strains. Slide 2: SUS vs. PYR S. fugiperda strains. Biological replicates: 4 pools of RNA extracted from four pools of 5 second instar larvae. Technical Replicates: None, the biological replicates incorporated a dye swap. Total replication: four replicates for each strain.