Search results for "PORIN"
showing 10 items of 260 documents
Tonoplast aquaporins facilitate lateral root emergence\ud
2016
Pôle SPE IPM UB; International audience; Aquaporins (AQPs) are water channels allowing fast and passive diffusion of water across cell membranes. It was hypothesized that AQPs contribute to cell elongation processes by allowing water influx across the plasma membrane and the tonoplast to maintain adequate turgor pressure. Here, we report that, in Arabidopsis (Arabidopsis thaliana), the highly abundant tonoplast AQP isoforms AtTIP1;1, AtTIP1;2, and AtTIP2;1 facilitate the emergence of new lateral root primordia (LRPs). The number of lateral roots was strongly reduced in the triple tip mutant, whereas the single, double, and triple tip mutants showed no or minor reduction in growth of the mai…
Insect Vectors (Hemiptera: Cixiidae) and Pathogens Associated with the Disease Syndrome “Basses Richesses” of Sugar Beet in France
2019
International audience; The syndrome “basses richesses” (SBR) is a disease of sugar beet in eastern France associated with two phloem-restricted, nonculturable plant pathogens: a stolbur phytoplasma and a γ-3 proteobacterium, here called SBR bacterium. Three planthopper (Hemiptera: Cixiidae) species were found to live near and within sugar beet fields in eastern France: Cixius wagneri, Hyalesthes obsoletus, and Pentastiridius leporinus. The role of these planthoppers in spreading the two pathogens to sugar beet was studied. Based on its abundance and high frequency of infection with the SBR bacterium, P. leporinus was considered to be the economic vector of SBR disease. C. wagneri, the prim…
Characterization and evolution of two bacteriome-inhabiting symbionts in cixiid planthoppers (Hemiptera: Fulgoromorpha: Pentastirini).
2009
International audience; Like other plant sap-sucking insects, planthoppers within the family Cixiidae (Insecta: Hemiptera: Fulgoromorpha) host a diversified microbiota. We report the identification and first molecular characterization of symbiotic bacteria in cixiid planthoppers (tribe: Pentastirini). Using universal eubacterial primers we first screened the eubacterial 16S rRNA sequences in Pentastiridius leporinus (Linnaeus) with PCR amplification, cloning, and restriction fragment analysis. We identified three main 16S rRNA sequences that corresponded to a Wolbachia bacterium, a plant pathogenic bacterium, and a novel gammaproteobacterial symbiont. A fourth bacterial species affiliated w…
Activation of MAPK homologues by elicitors in tobacco cells
1998
Elicitors of plant defence reactions (such as cryptogein, an elicitin produced by Phytophthora cryptogea, or oligogalacturonides (OGs)), induced in tobacco cell suspensions (Nicotiana tabacum var Xanthi) a rapid and transient activation of two protein kinases (PKs) with apparent molecular masses of 50 and 46 kDa, respectively. These PKs activated and phosphorylated at tyrosine residues, phosphorylated myelin basic protein (MBP) at serine/threonine residues. Both are recognized by anti-MAPK antibodies. The two MBP kinases possessed the same kinetics of activation, and their activation depended, to the same extent, on different exogenously applied compounds (staurosporine, lanthanum, EGTA). W…
Cytosolic pH regulates root water transport during anoxic stress through gating of aquaporins.
2003
Flooding of soils results in acute oxygen deprivation (anoxia) of plant roots during winter in temperate latitudes, or after irrigation1, and is a major problem for agriculture. One early response of plants to anoxia and other environmental stresses is downregulation of water uptake due to inhibition of the water permeability (hydraulic conductivity) of roots (Lpr)2,3,4,5. Root water uptake is mediated largely by water channel proteins (aquaporins) of the plasma membrane intrinsic protein (PIP) subgroup6,7,8. These aquaporins may mediate stress-induced inhibition of Lpr2,4,9 but the mechanisms involved are unknown. Here we delineate the whole-root and cell bases for inhibition of water upta…
Agronomic practices as potential sustainable options for the management ofPentastiridius leporinus(Hemiptera: Cixiidae) in sugar beet crops
2009
International audience; Cixiid planthoppers (Hemiptera: Fulgoromorpha: Cixiidae) have been shown to vector phloem-limited prokaryotes associated to prominent plant diseases world-wide. However, little information is available on the management of such insects that spend a significant part of their life cycle underground as nymphal stages. Preliminary assays were carried out to analyse the potential of some agronomic practices to reduce the underground populations of Pentastiridius leporinus, a cixiid vector of plant pathogenic bacteria to sugar beets that completes its life cycle in the cropping rotation sugar beet-winter wheat. A first field assay was carried out to test the effect of spri…
Involvement of Free Calcium in Action of Cryptogein, a Proteinaceous Elicitor of Hypersensitive Reaction in Tobacco Cells
1995
Treatment of suspension-cultured tobacco (Nicotiana tabacum var Xanthi) cells with cryptogein, a proteinaceous elicitor from Phytophthora cryptogea, induced a great stimulation of Ca2+ influx within the first minutes. Ca2+ influx is essential for the initiation of cryptogein-induced responses, since ethyleneglycol-bis([beta]-amino-ethyl ether)-N,N[prime]-tetraacetic acid or La3+, which block Ca2+ entrance, suppress cryptogein-induced responses such as extracellular alkalinization, active oxygen species, and phytoalexin production. Moreover, once initiated, these responses require sustained Ca2+ influx within the 1st h. A Ca2+ ionophore (A23187) was able to trigger an extracellular alkaliniz…
Phosphoproteins Involved in the Signal Transduction of Cryptogein, an Elicitor of Defense Reactions in Tobacco
2000
We previously reported that the signal transduction of cryptogein, an elicitor of defense reactions in Nicotiana tabacum cells, involves upstream protein phosphorylation. In the present study, induction of these early physiological events was further investigated with inhibitors of protein phosphatase (PP), okadaïc acid, and calyculin A. Calyculin A mimicked the effects of cryptogein, inducing an influx of calcium, an extracellular alkalinization, and the production of active oxygen species (AOS), suggesting that during cryptogein signal transduction the balance between specific protein kinase (PK) and PP activities was modified. To identify the phosphorylated proteins that could be involv…
Distinct lytic vacuolar compartments are embedded inside the protein storage vacuole of dry and germinating Arabidopsis thaliana seeds.
2011
International audience; Plant cell vacuoles are diverse and dynamic structures. In particular, during seed germination, the protein storage vacuoles are rapidly replaced by a central lytic vacuole enabling rapid elongation of embryo cells. In this study, we investigate the dynamic remodeling of vacuolar compartments during Arabidopsis seed germination using immunocytochemistry with antibodies against tonoplast intrinsic protein (TIP) isoforms as well as proteins involved in nutrient mobilization and vacuolar acidification. Our results confirm the existence of a lytic compartment embedded in the protein storage vacuole of dry seeds, decorated by γ-TIP, the vacuolar proton pumping pyrophospha…
Protein phosphorylation is induced in tobacco cells by the elicitor cryptogein
1994
Changes in plasmalemma ion fluxes were observed when tobacco (Nicotiana tabacum) cells were treated with cryptogein, a proteinaceous elicitor from Phytophthora cryptogea. A strong alkalization of the culture medium, accompanied by a leakage of potassium, was induced within a few minutes of treatment. These effects reached a maximum after 30 to 40 min and lasted for several hours. This treatment also resulted in a rapid, but transient, production of activated oxygen species. All these physiological responses were fully sensitive to staurosporine, a known protein kinase inhibitor. Furthermore, a study of protein phosphorylation showed that cryptogein induced a staurosporine-sensitive phosphor…