33 research outputs found

    Development of Ophiocordyceps sinensis through Plant-Mediated Interkingdom Host Colonization

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    Ophiocordyceps sinensis is a well-known entomogenous and medicinal fungus. After its anamorphs parasitize the larvae of the genus Thitarodes, fruit-bodies may form to be used as medicine. However, its developmental mechanisms remain unknown. The distribution of O. sinensis was determined in different tissues of the Thitarodes larvae and the dominant plant species using real-time quantitative polymerase chain reaction (qPCR) and fluorescence in situ hybridization (FISH) technique, respectively. We found that more fungal material was located in plants than in larvae, especially in Ranunculus tanguticus. A considerable amount was detected in larval intestinal-wall and plant roots. It is suggested that plants are the potential hosts of O. sinensis, which modifies our understanding of the life cycle of O. sinensis and indicates that the phytophagous larvae may become infected as they feed. Our research may contribute to the study of systematic evolution and population ecology of O. sinensis, elucidate its developmental mechanism and promote sustainable harvesting

    Identification and functional characterization of D-fructose receptor in an egg parasitoid, Trichogramma chilonis.

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    In insects, the gustatory system has a critical function not only in selecting food and feeding behaviours but also in growth and metabolism. Gustatory receptors play an irreplaceable role in insect gustatory signalling. Trichogramma chilonis is an effective biocontrol agent against agricultural insect pests. However, the molecular mechanism of gustation in T. chilonis remains elusive. In this study, we found that T. chilonis adults had a preference for D-fructose and that D-fructose contributed to prolong longevity and improve fecundity. Then, We also isolated the full-length cDNA encoding candidate gustatory receptor (TchiGR43a) based on the transcriptome data of T. chilonis, and observed that the candidate gustatory receptor gene was expressed from the larval to adult stages. The expression levels of TchiGR43a were similar between female and male. A Xenopus oocyte expression system and two-electrode voltage-clamp recording further verified the function analysis of TchiGR43a. Electrophysiological results showed that TchiGR43a was exclusively tuned to D-fructose. By the studies of behaviour, molecular biology and electrophysiology in T. chilonis, our results lay a basic fundation of further study on the molecular mechanisms of gustatory reception and provide theoretical basis for the nutritional requirement of T. chilonis in biocontrol

    Molecular characterization and expression of six heat shock protein genes in relation to development and temperature in Trichogramma chilonis.

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    Trichogramma is a kind of egg parasitoid wasp that is widely used to control lepidopterous pests. Temperature is one of the main factors that determines the various life activities of this species, including development, reproduction and parasitism efficiency. Heat shock proteins (HSPs) are highly conserved and ubiquitous proteins that are best known for their responsiveness to temperature and other stresses. To explore the potential role of HSPs in Trichogramma species, we obtained the full-length cDNAs of six HSP genes (Tchsp10, Tchsp21.6, Tchsp60, Tchsp70, Tchsc70-3, and Tchsp90) from T. chilonis and analyzed their expression patterns during development and exposure to temperature stress. The deduced amino acid sequences of these HSP genes contained the typical signatures of their corresponding protein family and showed high homology to their counterparts in other species. The expression levels of Tchsp10, Tchsp21.6 and Tchsp60 decreased during development. However, the expression of Tchsc70-3 increased from the pupal stage to the adult stage. Tchsp70 and Tchsp90 exhibited the highest expression levels in the adult stage. The expression of six Tchsps was dramatically upregulated after 1 h of exposure to 32 and 40°C but did not significantly change after 1 h of exposure to 10 and 17°C. This result indicated that heat stress, rather than cold stress, induced the expression of HSP genes. Furthermore, the expression of these genes was time dependent, and the expression of each gene reached its peak after 1 h of heat exposure (40°C). Tchsp10 and Tchsp70 exhibited a low-intensity cold response after 4 and 8 h of exposure to 10°C, respectively, but the other genes did not respond to cold at any time points. These results suggested that HSPs may play different roles in the development of this organism and in its response to temperature stress

    Analysis of the Transcriptome of Blowfly <i>Chrysomya megacephala</i> (Fabricius) Larvae in Responses to Different Edible Oils

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    <div><p>Background</p><p><i>Chrysomya megacephala</i> (Fabricius), a prevalent necrophagous blowfly that is easily mass reared, is noted for being a mechanical vector of pathogenic microorganisms, a pollinator of numerous crops, and a resource insect in forensic investigation in the postmortem interval. In the present study, in order to comprehensively understand the physiological and biochemical functions of <i>C. megacephala</i>, we performed RNA-sequencing and digital gene expression (DGE) profiling using Solexa/Illumina sequencing technology.</p><p>Methodology/Principal Findings</p><p>A total of 39,098,662 clean reads were assembled into 27,588 unigenes with a mean length of 768 nt. All unigenes were searched against the Nt database, Nr database, Swiss-Prot, Cluster of Orthologous Groups (COG) and Kyoto Encyclopedia of Genes and Genome (KEGG) with the BLASTn or BLASTx algorithm (E-value<0.00001) for annotations. In total, 7,081 unigenes and 14,099 unigenes were functionally classified into 25 COG categories and 240 KEGG pathways, respectively. Furthermore, 20,216 unigenes were grouped into 48 sub-categories belonging to 3 main Gene Ontology (GO) categories (ontologies). Using the transcriptome data as references, we analyzed the differential gene expressions between a soybean oil-fed group (SOF) and a lard oil-fed group (LOF), compared to the negative control group (NC), using the DGE approach. We finally obtained 1,566 differentially expressed genes in SOF/NC, and 1,099 genes in LOF/NC. For further analysis, GO and KEGG functional enrichment were performed on all differentially expressed genes, and a group of differentially expressed candidate genes related to lipometabolism were identified.</p><p>Conclusions/Significance</p><p>This study provides a global survey of <i>C. megacephal</i>a and provides the basis for further research on the functional genomics of this insect.</p></div

    Histogram presentation of COG function classification of Unigenes.

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    <p>7,081 unigenes were classified functionally into 25 COG categories.</p

    qRT-PCR validation of DGE results.

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    <p>The left y-axis indicates the relative expression level obtained by qRT-PCR (2<sup>−ΔΔCt</sup>), which were presented as fold changes in gene expression normalized to the <i>actin</i> gene in each group, and the right y-axis indicates the TPM (transcripts per million mapped reads) obtained by DGE.</p
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