Search results for "CELLULAR"
showing 10 items of 6449 documents
Arabidopsis SGS2 and SGS3 genes are required for posttranscriptional gene silencing and natural virus resistance.
2000
AbstractPosttranscriptional gene silencing (PTGS) in plants results from the degradation of mRNAs and shows phenomenological similarities with quelling in fungi and RNAi in animals. Here, we report the isolation of sgs2 and sgs3 Arabidopsis mutants impaired in PTGS. We establish a mechanistic link between PTGS, quelling, and RNAi since the Arabidopsis SGS2 protein is similar to an RNA-dependent RNA polymerase like N. crassa QDE-1, controlling quelling, and C. elegans EGO-1, controlling RNAi. In contrast, SGS3 shows no significant similarity with any known or putative protein, thus defining a specific step of PTGS in plants. Both sgs2 and sgs3 mutants show enhanced susceptibility to virus, d…
Organelle protein changes in arbuscular mycorrhizal Medicago truncatula roots as deciphered by subcellular proteomics
2019
Prod 2020-8c SPE IPM INRA UB CNRS; The roots of most land plants can enter a symbiotic relationship with arbuscular mycorrhizal (AM) soil‐borne fungi belonging to the phylum Glomeromycota, which improves the mineral nutrition of the host plant. The fungus enters the root through the epidermis and grows into the cortex where it differentiates into a highly branched hyphal structure called the arbuscule. The role of the plant membrane system as the agent for cellular morphogenesis and signal/nutrient exchanges is especially accentuated during AM endosymbiosis. Notably, fungal hyphae are always surrounded by the host membrane, which is referred to as the perifungal membrane around intracellula…
Engineering CRISPR guide RNA riboswitches for in vivo applications
2019
CRISPR-based genome editing provides a simple and scalable toolbox for a variety of therapeutic and biotechnology applications. Whilst the fundamental properties of CRISPR proved easily transferable from the native prokaryotic hosts to eukaryotic and multicellular organisms, the tight control of the CRISPR-editing activity remains a major challenge. Here we summarise recent developments of CRISPR and riboswitch technologies and recommend novel functionalised synthetic-gRNA (sgRNA) designs to achieve inducible and spatiotemporal regulation of CRISPR-based genetic editors in response to cellular or extracellular stimuli. We believe that future advances of these tools will have major implicati…
Nitric oxide signalling in plants: interplays with Ca2+ and protein kinase
2008
International audience; Much attention has been paid to nitric oxide (NO)research since its discovery as a physiological mediator of plant defence responses. In recent years, newer roles have been attributed to NO, ranging from root development to stomatal closure. The molecular mechanisms underlying NO action in plants are just begun to emerge. The currently available data illustrate that NO can directly influence the activity of target proteins through nitrosylation and has the capacity to act as a Ca2+-mobilizing intracellular messenger. The interplay between NO and Ca2+ has important functional implications, expanding and enriching the possibilities for modulating transduction processes…
Distribution of sea urchins living near shallow water CO2 vents is dependent upon species acid-base and ion-regulatory abilities.
2013
To reduce the negative effect of climate change on Biodiversity, the use of geological CO2 sequestration has been proposed; however leakage from underwater storages may represent a risk to marine life. As extracellular homeostasis is important in determining species' ability to cope with elevated CO2, we investigated the acid-base and ion regulatory responses, as well as the density, of sea urchins living around CO2 vents at Vulcano, Italy. We conducted in situ transplantation and field-based laboratory exposures to different pCO2/pH regimes. Our results confirm that sea urchins have some ability to regulate their extracellular fluid under elevated pCO2. Furthermore, we show that even in cl…
The Selaginella Genome Identifies Genetic Changes Associated with the Evolution of Vascular Plants
2011
International audience; Vascular plants appeared ~410 million years ago, then diverged into several lineages of which only two survive: the euphyllophytes (ferns and seed plants) and the lycophytes. We report here the genome sequence of the lycophyte Selaginella moellendorffii (Selaginella), the first nonseed vascular plant genome reported. By comparing gene content in evolutionarily diverse taxa, we found that the transition from a gametophyte- to a sporophyte-dominated life cycle required far fewer new genes than the transition from a nonseed vascular to a flowering plant, whereas secondary metabolic genes expanded extensively and in parallel in the lycophyte and angiosperm lineages. Sela…
Sugar transporters in plants and in their interactions with fungi.
2012
International audience; Sucrose and monosaccharide transporters mediate long distance transport of sugar from source to sink organs and constitute key components for carbon partitioning at the whole plant level and in interactions with fungi. Even if numerous families of plant sugar transporters are defined; efflux capacities, subcellular localization and association to membrane rafts have only been recently reported. On the fungal side, the investigation of sugar transport mechanisms in mutualistic and pathogenic interactions is now emerging. Here, we review the essential role of sugar transporters for distribution of carbohydrates inside plant cells, as well as for plant fungal interactio…
The plasma membrane oxidase NtrbohD is responsible for AOS production in elicited tobacco cells
2002
Summary A cDNA encoding a protein, NtrbohD, located on the plasma membrane and homologue to the flavocytochrome of the neutrophil NADPH oxidase, was cloned in tobacco. The corresponding mRNA was accumulated when tobacco leaves and cells were treated with the fungal elicitor cryptogein. After elicitation with cryptogein, tobacco cells transformed with antisense constructs of NtrbohD showed the same extracellular alkalinization as the control, but no longer produced active oxygen species (AOS). This work represents the first demonstration of the function of a homologue of gp91–phox in AOS production in elicited tobacco cells.
The Ectocarpus Genome and Brown Algal Genomics
2012
Brown algae are important organisms both because of their key ecological roles in coastal ecosystems and because of the remarkable biological features that they have acquired during their unusual evolutionary history. The recent sequencing of the complete genome of the filamentous brown alga Ectocarpus has provided unprecedented access to the molecular processes that underlie brown algal biology. Analysis of the genome sequence, which exhibits several unusual structural features, identified genes that are predicted to play key roles in several aspects of brown algal metabolism, in the construction of the multicellular bodyplan and in resistance to biotic and abiotic stresses. Information fr…
Infection by Endosymbiotic “Male-Killing” Bacteria in Coleoptera
2018
Wolbachia, Rickettsia, Spiroplasma and Cardinium are endosymbiotic and intracellular bacteria known to cause numerous disorders in host reproduction, reflected in their common name “male-killers”. In this study, 297 beetle species from various taxonomic groups were screened with the use of molecular markers for the presence of infection by any of these endosymbionts. Wolbachia was found to be the most common “male-killer” among beetle hosts as it infected approx. 27% of species. Rickettsia, Spiroplasma and Cardinium were much less prevalent as they infected: 8%, 3% and 2%, respectively, of the studied beetle species. This is the first report of Cardinium presence in beetle hosts. Incidences…