Project description:Laodelphax striatellus is naturally infected with the Wolbachia strain wStri, which significantly increase the fecundity of its host. Wolbachia-infected females produce 30%–40% more eggs than Wolbachia-uninfected females. MicroRNAs (miRNAs) are a class of endogenous non-coding small RNAs that play critical roles in the regulation of gene expression at post-transcriptional level. Here we report the differentially expressed miRNAs between Wolbachia-infected and Wolbachia-uninfected strains of L. striatellus ovaries. Our data may be helpful to explore the molecular mechanisms by which Wolbachia increase the fecundity of Laodelphax striatellus.
Project description:The Periconia genus belongs to the phylum Ascomycota, order Pleosporales, family Periconiaceae. Periconia is widespread in many habitats but little is known about its ecology. Several species produce bioactive molecules, among them, Periconia digitata extracts were shown to be deadly active against the pine wilt nematode. The strain CNCM I-4278, here identified as P. digitata was able to inhibit the plant pathogen Phytophthora parasitica. Since P. digitata has great potential as biocontrol agent and the only other genome available in the Periconiaceae family is that of Periconia macrospinosa, which is quite fragmentary, we generated long-read genomic data for P. digitata. Thanks to the PacBio Hifi sequencing technology, we obtained a high-quality genome with a total length of 38,967,494 bp, represented by 13 haploid chromosomes. The transcriptomic and proteomic data strengthen and support the genome annotation. Besides representing a new reference genome within the Periconiaceae, this work will also contribute in our understanding of the Eukaryotic tree of life. Not least, opens new possibilities to the biotechnological use of the species.
Project description:The Periconia genus belongs to the phylum Ascomycota, order Pleosporales, family Periconiaceae. Periconia is widespread in many habitats but little is known about its ecology. Several species produce bioactive molecules, among them, Periconia digitata extracts were shown to be deadly active against the pine wilt nematode. The strain CNCM I-4278, here identified as P. digitata was able to inhibit the plant pathogen Phytophthora parasitica. Since P. digitata has great potential as biocontrol agent and the only other genome available in the Periconiaceae family is that of Periconia macrospinosa, which is quite fragmentary, we generated long-read genomic data for P. digitata. Thanks to the PacBio Hifi sequencing technology, we obtained a high-quality genome with a total length of 38,967,494 bp, represented by 13 haploid chromosomes. The transcriptomic and proteomic data strengthen and support the genome annotation. Besides representing a new reference genome within the Periconiaceae, this work will also contribute in our understanding of the Eukaryotic tree of life. Not least, opens new possibilities to the biotechnological use of the species.
Project description:The dengue virus (DENV) cause frequent epidemics infecting ~390 million people annually in over 100 countries. There are no approved vaccines or antiviral drugs for treatment of infected patients. However, there is a novel approach to control transmission of DENV by the mosquito vectors, Aedes aegypti and Ae. albopictus, using Wolbachia symbiont. The wMelPop strain of Wolbachia suppresses DENV transmission and shortens the mosquito life span. However, the underlying mechanism is poorly understood. To clarify this mechanism, either naïve Ae. albopictus (C6/36) or wMelPop-C6/36 cells were infected with DENV2. Analysis of host transcript profiles by RNAseq revealed that the presence of wMelPop had profound effects on mosquito host cell transcription in response to DENV2 infection. The viral RNA evolved from wMelPop-C6/36 contained low frequency mutations (~25%) within the coding region of transmembrane domain-1 (TMD1) of E protein. Mutations with >97 % frequencies were distributed within other regions of E, NS5 RNA-dependent RNA polymerase (NS5POL) domain, the TMDs of NS2A, NS2B, and NS4B. Moreover, while DENV2-infected naïve C6/36 cells showed syncytia formation, DENV2-infected wMelPop-C6/36 cells did not. The Wolbachia-induced mutant DENV2 can readily infect and replicate in naïve C6/36 cells; whereas, in the mutant DENV2- infected BHK-21 or Vero cells, the virus replication was delayed. In LLC-MK2 cells, the mutant failed to produce plaques. Additionally, in BHK-21 cells, many mutations in the viral genome reverted to WT and compensatory mutations in NS3 gene appeared. Our results suggest that wMelPop impacts significantly the interactions of DENV2 with mosquito and mammalian host cells.
Project description:We characterized the miRNA composition of the nucleus and the cytoplasm of uninfected cells and compared it with the one of cells infected with the endosymbiotic bacterium Wolbachia strain wMelPop-CLA. We found an overall increase of small RNAs between 18 and 28 nucleotides in both cellular compartments in Wolbachia-infected cells and identified specific miRNAs induced and/or suppressed by the Wolbachia infection. We discuss the mechanisms that the cell may use to shuttle miRNAs between the cytoplasm and the nucleus. In addition, we identified piRNAs that changed their abundance in response to Wolbachia infection. The miRNAs and piRNAs identified in this study provide promising leads for investigations into the host-endosymbiont interactions and for better understanding of how Wolbachia manipulates the host miRNA machinery in order to facilitate its persistent replication in infected cells.
Project description:Wolbachia is a maternally transmitted bacterium that manipulates arthropod and nematode biology in myriad ways. The Wolbachia strain colonizing Drosophila melanogaster creates sperm-egg incompatibilities and protects its host against RNA viruses, making it a promising tool for vector control. Despite successful trials using Wolbachia-transfected mosquitoes for Dengue control, knowledge of how Wolbachia and viruses jointly affect insect biology remains limited. Using the Drosophila melanogaster model, transcriptomics and gene expression network analyses revealed pathways with altered expression and splicing due to Wolbachia colonization and virus infection. Included are metabolic pathways previously unknown to be important for Wolbachia-host interactions. Additionally, Wolbachia-colonized flies exhibit a dampened transcriptomic response to virus infection, consistent with early blocking of virus replication. Finally, using Drosophila genetics, we show Wolbachia and expression of nucleotide metabolism genes have interactive effects on virus replication. Understanding the mechanisms of pathogen blocking will contribute to the effective development of Wolbachia-mediated vector control programs.
Project description:The Drosophila-Wolbachia system is being used to study the molecular nature of the interactions between a host and a symbiont. This system offers a unique opportunity for such a study since the Drosophila genome sequence is available, several Wolbachi genomes will also be available soon and there are at least three known Wolbachia strains infecting Drosophila: a) mod+ strain that induces cytoplasmic incompatibility, b) mod- strain that cannot induce cytoplasmic incompatibility, and c) popcorn strain, a virulent strain which reduces in half the adult lifespan of Drosophila due to its massive proliferation in adult brain. The Drosophila-Wolbachia interaction manifests itself in 3 main ways; first, destruction of the CNS in infected adults, second, induction of some kind of modification or imprinting in the male germ-line resulting in an early failure in embryonic development, (cytoplasmic incompatability (CI)) and third, modification of the female germ-line resulting in resistance to modified sperm. We are interested in identifying Drosophila genes with changes in expression due to Wolbachia infection. We have generated a series of isogenic fly lines (those being used in the IGF P-element project) which we have infected with Wolbachia strains, infection is readily cured by growth on medium containing tetracycline. Thus, we have equivalent genetic background with and without the parasite. We have tested all of the transgenic lines for the level of CI and find strain-specific levels ranging from 0-50%. We also have a strain of D. simulans that shows over 95% CI. Plan: For our initial experiments we wish to make 4 comparisons, in all cases 2 day old males will be collected and for each comparison we will isolate 3 independent biological replicates: Melanogaster no CI [tet] x Melanogaster no CI [+wol] Melanogaster high CI [tet] x Melanogaster high CI [+wol] We will therefore identify genes with changed expression levels in the male upon Wolbachia infection by comparing the melanogaster strains with high or no CI in the presence of tetracycline and Wolbachia. We also hope to identify similar genes in simulans (where we expect the magnitude of the effect to be larger), differences between melanogaster and simulans are controlled for in the mel v sim comparison.
Project description:Using microarray-based comparative genome hybridizations (mCGH), the genomic content of Wolbachia pipientis wMel from Drosophila melanogaster was compared to the Wolbachia from D. innubila (wInn), D. santomea (wSan), and three strains from D. simulans (wAu, wRi, wSim).
Project description:DNA binding protein are generally thought to bind specific DNA sequences through selective interactions with DNA bases. However, it is now becoming more widely appreciated that DNA shape, which may not be specified by a unique base sequence, also contributes to site-specific binding. Here we elucidate how DNA sequence and shape confer site specificity on a genomic scale, and relate this to specificity imparted indirectly through occlusion of sequences by the in vivo environment. For simplicity, we focus on the set of General Regulatory Factors (GRFs) that do not rely on other factors for binding. They also serve a related function in organizing chromatin. Remarkably, we find that GRFs will not bind to their cognate motif if the DNA surrounding that sequence lacks a specific shape. While proper DNA sequence/shape properties tend to be restricted to promoter regions, weaker sites that are still binding-competent reside in gene bodies, but are prevented from binding by resident chromatin. Thus, site-specificity is achieved across a genome in vivo by the combined action of favorable DNA sequence and shape interactions, and occlusion by chromatin.