Project description:Aphid saliva plays an essential role in the interaction between aphids and their host plants. Several aphid salivary proteins have been identified and analyzed. However, none of the characterized salivary proteins are from galling aphids. Here we analyzed the salivary proteins from the Chinese gall aphid, Schlechtendalia chinensis using LS-MS/MS analysis. A total of 31 proteins were identified directly from secreted saliva collected via artificial diet, and 141 proteins were identified from protein extracts derived from dissected salivary glands. Among these identified proteins, 17 were found in both secreted saliva and dissected salivary glands. In comparison with salivary proteins identified from three other free living aphids, the most striking feature of the salivary protein from S. chinensis is the existence of high proportion of proteins with binding activity, including DNA binding, protein binding, ATP binding and ion binding proteins et al. We speculate that these binding proteins may be involved in induction of gall formation. Our results provide a framework for future research to elucidate the molecular basis for gall induction by S. chinensis.
Project description:Aphid saliva plays an essential role in the interaction between aphids and their host plants. Several aphid salivary proteins have been identified and analyzed. However, none of the characterized salivary proteins are from galling aphids. Here we analyzed the salivary proteins from the Chinese gall aphid, Schlechtendalia chinensis using LS-MS/MS analysis. A total of 31 proteins were identified directly from secreted saliva collected via artificial diet, and 141 proteins were identified from protein extracts derived from dissected salivary glands. Among these identified proteins, 17 were found in both secreted saliva and dissected salivary glands. In comparison with salivary proteins identified from three other free living aphids, the most striking feature of the salivary protein from S. chinensis is the existence of high proportion of proteins with binding activity, including DNA binding, protein binding, ATP binding and ion binding proteins et al. We speculate that these binding proteins may be involved in induction of gall formation. Our results provide a framework for future research to elucidate the molecular basis for gall induction by S. chinensis.
Project description:Background: Aphids are economically important pests and that display exceptional variation in host range. The underlying mechanism of diverse aphid host ranges are not well understood, but it is likely that molecular interactions are involved. With significant progress being made towards understanding host responses upon aphid attack, the mechanisms underlying nonhost resistance remain to be elucidated. Here, we investigated and compared Arabidopsis host and nonhost responses to aphids at the transcriptome level using three different aphid species. Results: Gene expression analyses revealed a surprising level of overlap in the overall gene expression changes during host and nonhost interactions with regards to the sets of genes differentially expressed and the direction of expression changes. Despite the overlap in transcriptional responses across interactions, there was a stronger repression of genes involved in metabolism and oxidative responses specifically during the host interaction. In addition we indentified a set of genes with opposite gene expression patterns during host versus nonhost interactions. Aphid performance assays on Arabidopsis mutants selected based on our transcriptome analyses identified genes involved in host and nonhost interactions. Conclusions: Understanding how plants respond to aphid species that differ in their ability to infest plant species, and identifying the genes and signaling pathways involved, is essential for the development of novel and durable aphid control in crop plants. Our work is an important step forward to provide such essential insights in that we identified novel genes contributing to host susceptibility, host defences as well nonhost resistance to aphids.
Project description:Soybean aphid is one of the major limiting factors for soybean production. However, the mechanism for aphid resistance in soybean is remain enigmatic, very little information is available about the different mechanisms between antibiosis and antixenosis genotypes. Here we dissected aphid infestation into three stages and used genome-wide gene expression profiling to investigate the underlying aphid-plant interaction mechanisms. Approximately 990 million raw reads in total were obtained, the high expression correlation in each genotype between infestation and non-infestation indicated that the response to aphid was controlled by a small subset of important genes. Moreover, plant response to aphid infestation was more rapid in resistant genotypes. Among the differentially expressed genes (DEGs), a total of 901 transcription factor (TF) genes categorized to 40 families were identified with distinct expression patterns, of which AP2/ERF, MYB and WRKY families were proposed to playing dominated roles. Gene expression profiling demonstrated that these genes had either similar or distinct expression patterns in genotypes. Besides, JA-responsive pathway was domination in aphid-soybean interaction compared to SA pathway, which was not involved plant response to aphid in susceptible and antixenotic genotypes but played an important role in antibiosis one. Throughout, callose were deposited in all genotypes but it was more rapidly and efficiently in antibiotic one. However, reactive oxygen species were not involved in response to aphid attack in resistant genotypes during aphid infestation. Our study helps uncover important genes associated with aphid-attack response in antibiosis and antixenotic genotypes of soybean.
Project description:Oak galls form when gall wasps lay their eggs into part of the tree; in some galls, this attachment point to the host consists of only a few cells. The gall itself comprises entirely of host tissue; however, the initiation, development, and physical appearance are controlled by the inducer. This raises the intriguing question of the molecular mechanisms underlying gall formation, by which one or a small number of cells are reprogrammed and commit to a novel developmental path. Gall wasps undergo two generations each year, and the galls formed by these two generations exhibit markedly different appearances. We sequenced the transcriptomes of both the sexual and asexual generations of Neuropterus quercusbaccarum and Neuroterus numismalis. The transcriptomes of the generations that occur at the same time of year are more similar to each other than they are to the opposite generation of their respective species.
Project description:Some insects can redirect plant development to form unique organs called galls, which provide these insects with unique, enhanced food and protection from enemies and the elements. Many galls resemble flowers or fruits, suggesting that elements of reproductive development may be involved. We addressed this possibility using RNA sequencing (RNAseq) to quantify the transcriptional responses of wild grapevine (Vitis riparia Michx.) leaves to a galling parasite, phylloxera (Daktulosphaira vitifoliae (Fitch 1855)). If development of reproductive structures is part of gall formation, we expected to find significantly elevated expression of genes involved in flower and/or fruit development in developing galls as opposed to ungalled leaves. We found that reproductive gene ontology classes were significantly enriched in developing galls, and that expression of many putative genes involved in flower formation was significantly increased, particularly in later gall stages. The patterns of gene expression found in galls suggest that phylloxera exploits vascular cambium to provide meristematic tissue and redirects leaf development towards formation of carpels. The phylloxera leaf gall, and perhaps other similar galls, appears to be phenotypically and transcriptionally convergent on the plant carpel.
Project description:A striking property of the ancient and obligate mutualism between figs and their pollinating wasps is that fig wasps consistently oviposit in the inner flowers of the fig syconium (gall flowers, which develop into galls that house developing larvae), but typically do not use the outer ring of flowers (seed flowers, which develop into seeds). To better understand differences between gall and seed flowers that might influence oviposition choices, and the unknown mechanisms underlying gall formation, we used a metatranscriptomic approach to analyze eukaryotic gene expression within fig flowers at the time of oviposition choice and early gall development. Consistent with the unbeatable seed hypothesis, which posits that only a portion of fig flowers are physiologically capable of responding to gall induction or supporting larval development, we found significant differences in gene expression assigned to defense and metabolism between gall- and seed flowers in receptive syconia. Transcripts assigned to flavonoids and defense were especially prevalent in receptive gall flowers, and carbohydrate metabolism was significantly up-regulated relative to seed flowers. In turn, high expression of the venom gene icarapin during wasp embryogenesis within galled flowers distinguishes it as a candidate gene for gall initiation. In response to galling, the fig significantly up-regulates the expression of chalcone synthase, which previously has been connected to gall formation in other plants. This study simultaneously evaluates the gene expression profile of both mutualistic partners in a plant-insect mutualism and provides evidence for a stability mechanism in the ancient fig-fig wasp association.