Project description:Spiders are a highly diverse group of arthropods that occur in most habitats on land. Notably, spiders have significant ecological impact as predators because of their extraordinary prey capture adaptations, venom and silk. Spider venom is among the most heterogeneous animal venoms and has pharmacological applications, while spider silk is characterized by great toughness with potential for biomaterial application. We describe the genome sequences of two spiders representing two major taxonomic groups, the social velvet spider Stegodyphus mimosarum (Araneomorphae), and the Brazilian white-knee tarantula Acanthoscurria geniculata (Mygalomorphae). We annotate genes using a combination of transcriptomic and in-depth proteomic analyses. The genomes are large (2.6 Gb and 6 Gb, respectively) with short exons and long introns and approximately 50% repeats, reminiscent of typical mammalian genomes. Phylogenetic analyses show that spiders and ticks are sister groups outgrouped by mites, and phylogenetic dating using a molecular clock dates separation of velvet spider and tarantula at 270 my. Based on the genomes and proteomes, we characterize the genetic basis of venom and silk production of both species in detail. Venom protein composition differs markedly between the two spiders, with lipases as the most abundant protein in the velvet spider and present only at low concentration in tarantula. Venom in both spiders contains proteolytic enzymes, and our analyses suggest that these enzymes target and process precursor peptides that subsequently mediate the toxic effects of venom. Complete analysis of silk genes reveal a diverse suite of silk proteins in the velvet spider including novel types of spidroins, and dynamic evolution of major ampullate spidroin genes, whereas silk protein diversity in tarantula is far less complex. The difference in silk proteins between species is consistent with a more complex silk gland morpholgy and use of three-dimentional capture webs consisting of multiple silk types in aranomorph spiders.
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: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:We utilized the eyeless sea anemone, Nematostella vectensis, to quantify gene expression differences between different colors of light (red, green, blue) and in constant darkness through comparisons of 96 transcriptomes
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.