Dataset Information

Pectinmethylesterase from the rice weevil, Sitophilus oryzae: cDNA isolation and sequencing, genetic origin, and expression of the recombinant enzyme.

ABSTRACT: A cDNA clone encoding pectinmethylesterase of the rice weevil, Sitophilus oryzae (L.) has been isolated and sequenced. The cDNA clone was expressed in cultured insect cells and active pectinmethylesterase was purified from the culture medium, thus confirming that the cDNA encodes pectinmethylesterase. In situ hybridization indicated that the enzyme's transcript was present in the midgut. Weevils treated with tetracycline so that they lack genes of known symbiotic organisms still contained the pectinmethylesterase gene, indicating that the gene is encoded by the rice weevil genome. The rice weevil enzyme is most similar in sequence to bacterial pectinmethylesterases. Given this and the enzyme's apparently rather general absence from animal species, we suggest the possibility that this gene was transferred horizontally to an ancient weevil, possibly from a bacterial symbiont, and exists in Sitophilus species now as a result of that ancestral horizontal transfer.

SUBMITTER: Shen Z

PROVIDER: S-EPMC1307582 | biostudies-literature | 2005

REPOSITORIES: biostudies-literature

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Pectinmethylesterase from the rice weevil, Sitophilus oryzae: cDNA isolation and sequencing, genetic origin, and expression of the recombinant enzyme.

Shen Zhicheng Z Pappan Kirk K Mutti Navdeep S NS He Qi-Jiong QJ Denton Michael M Zhang Yu Y Kanost Michael R MR Reese John C JC Reeck Gerald R GR

Journal of insect science (Online) 20050808

A cDNA clone encoding pectinmethylesterase of the rice weevil, Sitophilus oryzae (L.) has been isolated and sequenced. The cDNA clone was expressed in cultured insect cells and active pectinmethylesterase was purified from the culture medium, thus confirming that the cDNA encodes pectinmethylesterase. In situ hybridization indicated that the enzyme's transcript was present in the midgut. Weevils treated with tetracycline so that they lack genes of known symbiotic organisms still contained the pe ...[more]

PMID: 16341253

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Project description:In this study, many virus-like fragments were obtained from transcriptomes of three wasp species, including Anisopteromalus calandrae (8), Lariophagus distinguendus (3), and Theocolax elegans (18), which can parasitize and control rice weevil Sitophilus oryzae, a serious insect pest of farm-stored grains. By further bioinformatic analysis and sequencing, we identified six novel RNA viruses with complete genomes and named them WWPSRV-1, WWPSRV-2, AcPSRV-1, AcNSRV-1, AcNSRV-2, and LdNSRV-1. PCR-based detection revealed that WWPSRV-1 and WWPSRV-2 had the possibility of interspecies virus transmission, especially WWPSRV-2, which was also present in the rice weevil adults. Phylogenetically, three out of these six viruses appeared to be members of order Picornavirales: WWPSRV-1 belonged to unassigned virus families of this order, whereas WWPSRV-2 and AcPSRV-1 belonged to families Iflaviridae and Dicistroviridae, respectively. The conserved picornavirus-typical domains helicase, protease, and RNA-dependent RNA polymerase could be found in the nonstructural protein encoded by the three viruses, whose genomes consisted of the different numbers of open reading frames (ORFs). The other three RNA viruses could be classified to order Mononegavirales: AcNSRV-1 and AcNSRV-2 belonged to family Lispiviridae, whereas LdNSRV-1 belonged to a big family Rhabdoviridae The genomes of the three viruses contained at least five ORFs, encoding deduced proteins in the following order: 3'-N-P-M-G-L-5'. All the ORFs were separated by conserved intergenic sequences which likely regulated the transcription termination and initiation. Our findings enhance the understanding of RNA viruses in weevil wasps and set the foundation for the future study of the association among weevils, weevil wasps, and RNA viruses.IMPORTANCE The enormous diversity of RNA viruses in insects is continuously validated. Parasitoid wasps, as biocontrol insects which are widely used against insect pests in agroecosystems, may also carry many "good" RNA viruses. Some RNA viruses in parasitoid wasps have been reported to affect the host wasps or the wasps' host. Here, six novel RNA viruses with complete genomes were identified in three parasitoid wasps of the rice weevil. One of these viruses was also detected in the rice weevil adults. Phylogenetically, WWPSRV-1 was the first unambiguous detection of Nora-like virus in insect parasitoids. WWPSRV-2 and AcPSRV-1 belong to families Iflaviridae and Dicistroviridae, some viruses of which can result in lethal infections in silkworms and honeybees. The other three RNA viruses belong to order Mononegavirales, which comprises many well-known insect-associated viruses.

Project description:BackgroundInsects thriving on nutritionally poor habitats have integrated mutualistic intracellular symbiotic bacteria (endosymbionts) in a bacteria-bearing tissue (the bacteriome) that isolates the endosymbionts and protects them against a host systemic immune response. Whilst the metabolic and physiological features of long-term insect associations have been investigated in detail over the past decades, cellular and immune regulations that determine the host response to endosymbionts and pathogens have attracted interest more recently.ResultsTo investigate bacteriome cellular specificities and weevil immune responses to bacteria, we have constructed and sequenced 7 cDNA libraries from Sitophilus oryzae whole larvae and bacteriomes. Bioinformatic analysis of 26,886 ESTs led to the generation of 8,941 weevil unigenes. Based on in silico analysis and on the examination of genes involved in the cellular pathways of potential interest to intracellular symbiosis (i.e. cell growth and apoptosis, autophagy, immunity), we have selected and analyzed 29 genes using qRT-PCR, taking into consideration bacteriome specificity and symbiosis impact on the host response to pathogens. We show that the bacteriome tissue accumulates transcripts from genes involved in cellular development and survival, such as the apoptotic inhibitors iap2 and iap3, and endosomal fusion and trafficking, such as Rab7, Hrs, and SNARE. As regards our investigation into immunity, we first strengthen the bacteriome immunomodulation previously reported in S. zeamais. We show that the sarcotoxin, the c-type lysozyme, and the wpgrp2 genes are downregulated in the S. oryzae bacteriome, when compared to aposymbiotic insects and insects challenged with E. coli. Secondly, transcript level comparison between symbiotic and aposymbiotic larvae provides evidence that the immune systemic response to pathogens is decreased in symbiotic insects, as shown by the relatively high expression of wpgrp2, wpgrp3, coleoptericin-B, diptericin, and sarcotoxin genes in aposymbiotic insects.ConclusionsLibrary sequencing significantly increased the number of unigenes, allowing for improved functional and genetic investigations in the cereal weevil S. oryzae. Transcriptomic analyses support selective and local immune gene expression in the bacteriome tissue and uncover cellular pathways that are of potential interest to bacteriocyte survival and homeostasis. Bacterial challenge experiments have revealed that the systemic immune response would be less induced in a symbiotic insect, thus highlighting new perspectives on host immunity in long-term invertebrate co-evolutionary associations.

Dataset Information

Pectinmethylesterase from the rice weevil, Sitophilus oryzae: cDNA isolation and sequencing, genetic origin, and expression of the recombinant enzyme.

Publications

Pectinmethylesterase from the rice weevil, Sitophilus oryzae: cDNA isolation and sequencing, genetic origin, and expression of the recombinant enzyme.

Similar Datasets

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