Project description:Root nodule symbiosis (RNS) represents a significant phenotypic adaptation in plants to thrive in nitrogen-deficient environments. Recent findings propose a single gain of RNS at the crown of the nitrogen-fixing clade (NF clade). However, the genetic mechanisms underlying the origin and subsequent evolution of RNS remain largely unexplored. Here, we newly sequenced and assembled eleven genomes from the NF clade and studied genetic change along the evolution of RNS. Our results elucidated three key evolutionary stages leading to the formation of stable RNS between plants and symbiotic nitrogen-fixing bacteria.
Project description:Root nodule symbiosis (RNS) represents a significant phenotypic adaptation in plants to thrive in nitrogen-deficient environments. Recent findings propose a single gain of RNS at the crown of the nitrogen-fixing clade (NF clade). However, the genetic mechanisms underlying the origin and subsequent evolution of RNS remain largely unexplored. Here, we newly sequenced and assembled eleven genomes from the NF clade and studied genetic change along the evolution of RNS. Our results elucidated three key evolutionary stages leading to the formation of stable RNS between plants and symbiotic nitrogen-fixing bacteria.
Project description:Plasmodium multigene families are thought to play important roles in the pathogenesis of malaria. Plasmodium interspersed repeat (pir) genes comprise the largest multigene family in many Plasmodium species. However, their expression pattern and localisation remain to be elucidated. Protein subcellular localisation is fundamental to be able to elucidate the functional importance and cell-cell interactions of the PIR proteins. Here, we use the rodent malaria parasite, Plasmodium chabaudi chabaudi, as a model to investigate the localisation pattern of this gene family. We found that most PIR proteins are co-expressed in clusters during acute and chronic infection; members of the S7 clade are predominantly expressed during the acute-phase, whereas members of the L1 clade dominate the chronic-phase of infection. Using peptide antisera specific for S7 or L1 PIRS, we show that S7 and L1 PIRs have different localisations within the infected red blood cells. S7 PIRs are exported into the infected red blood cells cytoplasm where they are co-localised with parasite-induced host cell modifications termed Maurer's clefts, whereas L1 PIRs are localised on or close to the parasitophorous vacuolar membrane. This localisation pattern changes following mosquito transmission and during progression from acute- to chronic-phase of infection. However, neither S7 nor L1 PIR proteins detected by the peptide antisera are localised on the surface of infected red blood cells, suggesting that they are unlikely to be targets of surface variant-specific antibodies or be involved directly in adhesion of infected red blood cells to host cells, as described for Plasmodium falciparum VAR proteins. Their presence on Maurer’s clefts, as seen for Plasmodium falciparum RIFIN and STEVOR proteins, might further suggest trafficking of the PIRs on the surface of the infected erythrocytes. The differences in subcellular localisation of the two major clades of Plasmodium chabaudi PIRs across the blood cycle, and the apparent lack of expression on the red cell surface strongly suggest that the function(s) of this gene family may differ from those of other multigene families of Plasmodium, such as the var genes of Plasmodium falciparum.
Project description:This SuperSeries is composed of the following subset Series: GSE12809: Symbiodinium clade content drives host transcriptome more than thermal stress in the coral Montastraea faveolata (part 1) GSE15253: Symbiodinium clade content drives host transcriptome more than thermal stress in the coral Montastraea faveolata (part 2) Refer to individual Series
Project description:Small regulatory RNAs guide Argonaute (Ago) proteins in a sequence-specific manner to their targets and therefore have important roles in eukaryotic gene silencing. Of the three small RNA classes, microRNAs and short interfering RNAs are processed from double-stranded precursors into defined 21- to 23-mers by Dicer, an endoribonuclease with intrinsic ruler function. PIWI- interacting RNAs (piRNAs)—the 22–30-nt-long guides for PIWI- clade Ago proteins that silence transposons in animal gonads— are generated independently of Dicer from single-stranded precursors. piRNA 5′ ends are defined either by Zucchini, the Drosophila homologue of mitoPLD—a mitochondria-anchored endonuclease, or by piRNA-guided target cleavage. Formation of piRNA 3′ ends is poorly understood. Here we report that two genetically and mechanistically distinct pathways generate piRNA 3′ ends in Drosophila. The initiating nucleases are either Zucchini or the PIWI-clade proteins Aubergine (Aub)/Ago3. While Zucchini- mediated cleavages directly define mature piRNA 3′ ends, Aub/ Ago3-mediated cleavages liberate pre-piRNAs that require extensive resection by the 3′-to-5′ exoribonuclease Nibbler (Drosophila homologue of Mut-7). The relative activity of these two pathways dictates the extent to which piRNAs are directed to cytoplasmic or nuclear PIWI-clade proteins and thereby sets the balance between post-transcriptional and transcriptional silencing. Notably, loss of both Zucchini and Nibbler reveals a minimal, Argonaute-driven small RNA biogenesis pathway in which piRNA 5′ and 3′ ends are directly produced by closely spaced Aub/Ago3-mediated cleavage events. Our data reveal a coherent model for piRNA biogenesis, and should aid the mechanistic dissection of the processes that govern piRNA 3′-end formation.
Project description:Plasmodium yoelii is a rodent parasite commonly used as a model to study liver-stage development in host system during malaria infection. Mass spectrometry-based proteomics approaches helps in understanding the proteomic profiling of parasite and provided opportunities to explore the mechanisms controlling parasite functions. It will further help in identifying new targets for therapeutic interventions, identification of Plasmodium associated virulence in the host. It will also help in the extensive refinement of parasite genome, and understanding of Post-translational modifications (PTM) in Plasmodium yoelii biology. In the present study, we performed a proteomic shotgun analysis of the Plasmodium yoelii 17XNL strain.
Project description:Background The Lycophyta species are the extant taxa most similar to early vascular plants that were once abundant on Earth. However, their distribution has greatly diminished. So far, the absence of chromosome level assembled lycophyte genomes, has hindered our understanding of evolution and environmental adaption of lycophytes. Findings We present the reference genome of the tetraploid aquatic quillwort, Isoetes sinensis, a lycophyte. This genome represents the first chromosome-level assembled genome of a tetraploid seed-free plant. Comparison of genomes between I. sinensis and the diploid I. taiwanensis revealed of genomic features and polyploid of lycophytes. Comparison of the I. sinensis genome with those of other species representing the evolutionary lineages of green plants revealed the inherited genetic tools for transcriptional regulation and most phytohormones in I. sinensis. The presence and absence of key genes related to development and stress responses provides insights into environmental adaption of lycophytes. Conclusions The high-quality reference genome and genomic analysis presented in this study are crucial for future genetic research and the conservation of not only I. sinensis but also other lycophytes.
Project description:Background The Lycophyta species are the extant taxa most similar to early vascular plants that were once abundant on Earth. However, their distribution has greatly diminished. So far, the absence of chromosome level assembled lycophyte genomes, has hindered our understanding of evolution and environmental adaption of lycophytes. Findings We present the reference genome of the tetraploid aquatic quillwort, Isoetes sinensis, a lycophyte. This genome represents the first chromosome-level assembled genome of a tetraploid seed-free plant. Comparison of genomes between I. sinensis and the diploid I. taiwanensis revealed of genomic features and polyploid of lycophytes. Comparison of the I. sinensis genome with those of other species representing the evolutionary lineages of green plants revealed the inherited genetic tools for transcriptional regulation and most phytohormones in I. sinensis. The presence and absence of key genes related to development and stress responses provides insights into environmental adaption of lycophytes. Conclusions The high-quality reference genome and genomic analysis presented in this study are crucial for future genetic research and the conservation of not only I. sinensis but also other lycophytes.