Advancing on the understanding of the genome, gene expression, and potential for biotechnological exploitation of the polydnavirus associated with Cotesia flavipes.

Cotesia flavipes (Hymenoptera, Braconidae) in an efficient larval parasitoid of the sugarcane borer Diatraea saccharalis (Lepidoptera, Crambidae). C. flavipes was introduced and is successfully used in applied biological control programs over extensive areas of sugarcane production in Brazil. The successful exploitation of host larvae by Cotesia flavipes is related to a plethora of regulatory molecules this wasp injects into the host or that is produced by parasitoid-derived tissues and associated symbiotic virus (Polydnavirus ? PDV). PDVs produce several proteins that allow host colonization by immature parasitoids, as they affect the host immune system, regulate host metabolism and growth. PDV-derived proteins are an interesting source of molecules that could be used in developing genetically-modified plants suitable for sustainable pest management. In order to determine the diversity of proteins the PDV associated with Cotesia flavipes (CfPDV) and their production during parasitoid development, we obtained high throughput sequencing data and partially sequenced, annotated and compared the PDV genome of C. flavipes to other related PDVs. A set of PDV genes was selected and their expression in parasitized host larvae was assessed. In order to evaluate the potential for biotechnological exploitation of such proteins in pest control, candidate genes were selected and used for plant transformation to allow testing the effects of CfPDV proteins on non-preferred host insects

Primeiro registro de Diaphorina citri Kuwayama, 1908 (Hemiptera: Liviidade) para o estado de Roraima, Brasil.

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Variabilidade genética e feromonal de populações brasileiras de Spodoptera frugiperda (J.E. Smith) (Lepidoptera: noctuidae).

A lagarta do cartucho do milho, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) é uma das principais pragas de cultivos de milho nas Américas. No Brasil, o uso do feromônio sintético comercial recomendado para o monitoramento de S. frugiperda não tem apresentado uma captura eficiente de machos em algumas regiões do país. Assim, o presente trabalho tem por objetivo investigar a variabilidade genética e feromonal de populações brasileiras de S. frugiperda, visando contribuir para a melhoria da captura de machos em campo. Lagartas de S. frugiperda foram coletadas em cultivos de milho em diferentes regiões produtoras no país e criadas em laboratório. Os adultos provenientes dessas lagartas foram utilizados para extração e amplificação do DNA. As raças foram identificadas através da técnica de PCR-RFLP do gene mitocondrial citocromo-oxidase mediante a digestão com a endonuclease EcoRV e os haplótipos através do seqüenciamento dos produtos da PCR. O estudo da variabilidade genética inter e intra-populacional demonstrou a existência de duas raças distintas (arroz e milho), mesmo quando coletadas sobre o mesmo hospedeiro (milho). A contribuição de cada raça na composição das populações ao longo do país apresentou uma distribuição irregular entre as populações estudadas, no entanto, a raça predominante em todas as populações analisadas é a raça milho. Também foi verificada variação haplotípica entre diferentes populações do país, e entre indivíduos de um mesmo local. Estes dados indicam que a variabilidade genética encontrada nas populações de S. frugiperda pode representar uma potencial variação no feromônio produzido. Estes resultados poderão contribuir para o entendimento de uma possível variação na composição aos feromônios desta espécie, e no planejamento de uma estratégia de manejo com feromônio para as diferentes populações do país

Resposta de antena de machos de Spodoptera frugiperda (Lepidoptera: noctuidae) a compostos feromonais sintéticos.

Poster

Parasite Lost: Chemical and Visual Cues Used by Pseudacteon in Search of Azteca instabilis

An undescribed species of phorid fly (genus: Pseudacteon) parasitizes the ant Azteca instabilis F Smith, by first locating these ants through the use of both chemical and visual cues. Experiments were performed in Chiapas, Mexico to examine a) the anatomical source of phorid attractants, b) the specific chemicals produced that attract phorids, and c) the nature of the visual cues used by phorids to locate the ants. We determined that phorid-attracting chemicals were present within the dorsal section of the abdomen, the location of the pygidial gland. Further experiments indicate that a pygidial gland compound, 1-acetyl-2-methylcyclopentane, is at least partially responsible for attracting phorid flies to their host. Finally, although visual cues such as movement were important for host location, size and color of objects did not influence the frequency with which phorids attacked moving targets

The venom composition of the parasitic wasp Chelonus inanitus resolved by combined expressed sequence tags analysis and proteomic approach

<p>Abstract</p> <p>Background</p> <p>Parasitic wasps constitute one of the largest group of venomous animals. Although some physiological effects of their venoms are well documented, relatively little is known at the molecular level on the protein composition of these secretions. To identify the majority of the venom proteins of the endoparasitoid wasp <it>Chelonus inanitus </it>(Hymenoptera: Braconidae), we have randomly sequenced 2111 expressed sequence tags (ESTs) from a cDNA library of venom gland. In parallel, proteins from pure venom were separated by gel electrophoresis and individually submitted to a nano-LC-MS/MS analysis allowing comparison of peptides and ESTs sequences.</p> <p>Results</p> <p>About 60% of sequenced ESTs encoded proteins whose presence in venom was attested by mass spectrometry. Most of the remaining ESTs corresponded to gene products likely involved in the transcriptional and translational machinery of venom gland cells. In addition, a small number of transcripts were found to encode proteins that share sequence similarity with well-known venom constituents of social hymenopteran species, such as hyaluronidase-like proteins and an Allergen-5 protein.</p> <p>An overall number of 29 venom proteins could be identified through the combination of ESTs sequencing and proteomic analyses. The most highly redundant set of ESTs encoded a protein that shared sequence similarity with a venom protein of unknown function potentially specific of the <it>Chelonus </it>lineage. Venom components specific to <it>C. inanitus </it>included a C-type lectin domain containing protein, a chemosensory protein-like protein, a protein related to yellow-e3 and ten new proteins which shared no significant sequence similarity with known sequences. In addition, several venom proteins potentially able to interact with chitin were also identified including a chitinase, an imaginal disc growth factor-like protein and two putative mucin-like peritrophins.</p> <p>Conclusions</p> <p>The use of the combined approaches has allowed to discriminate between cellular and truly venom proteins. The venom of <it>C. inanitus </it>appears as a mixture of conserved venom components and of potentially lineage-specific proteins. These new molecular data enrich our knowledge on parasitoid venoms and more generally, might contribute to a better understanding of the evolution and functional diversity of venom proteins within Hymenoptera.</p