Search results for "Elicitor"
showing 10 items of 75 documents
Active oxygen species production in tobacco cells elicited by cryptogein*
1997
We analyse the relationship between active oxygen species (AOS) production and pH changes induced in tobacco cells by cryptogein, a fungal proteinaceous elicitor of defence mechanisms in plants. When tobacco cells were treated with cryptogein, an intracellular acidification, an alkalinization of the extracellular medium and a transient burst of AOS (H 2 O 2 ) were observed. Treatment of elicited cells with either diphenyleneiodonium (DPI), an inhibitor of the neutrophil NADPH oxidase, or Tiron, which scavenges O2 - , abolished AOS production. These data suggest the involvement of a NADPH oxidase-like enzyme leading to H 2 O 2 production through O 2 - dismutation. Although H 2 O 2 production…
Modification of Plasma Membrane Organization in Tobacco Cells Elicited by Cryptogein
2014
Abstract Lipid mixtures within artificial membranes undergo a separation into liquid-disordered and liquid-ordered phases. However, the existence of this segregation into microscopic liquid-ordered phases has been difficult to prove in living cells, and the precise organization of the plasma membrane into such phases has not been elucidated in plant cells. We developed a multispectral confocal microscopy approach to generate ratiometric images of the plasma membrane surface of Bright Yellow 2 tobacco (Nicotiana tabacum) suspension cells labeled with an environment sensitive fluorescent probe. This allowed the in vivo characterization of the global level of order of this membrane, by which w…
The fungal elicitor cryptogein is a sterol carrier protein
1997
AbstractCryptogein is a protein secreted by the phytopathogenic pseudo-fungus, Phytophthora cryptogea. It is a basic 10 kDa hydrophilic protein having a hydrophobic pocket and three disulfide bridges. These common features with sterol carrier proteins led us to investigate its possible sterol transfer activity using the fluorescent sterol, dehydroergosterol. The results show that cryptogein has one binding site with strong affinity for dehydroergosterol. Moreover, this protein catalyzes the transfer of sterols between phospholipidic artificial membranes. This is the first evidence for the existence of an extracellular sterol carrier protein and for a molecular activity of cryptogein. This p…
Fatty acids bind to the fungal elicitor cryptogein and compete with sterols
2001
Abstract Cryptogein is a proteinaceous elicitor of plant defense reactions which also exhibits sterol carrier properties. In this study, we report that this protein binds fatty acids. The stoichiometry of the fatty acid–cryptogein complex is 1:1. Linoleic acid and dehydroergosterol compete for the same site, but elicitin affinity is 27 times lower for fatty acid than for sterol. We show that C7 to C12 saturated and C16 to C22 unsaturated fatty acids are the best ligands. The presence of double bonds markedly increases the affinity of cryptogein for fatty acids. A comparison between elicitins and known lipid transfer proteins is discussed.
Calcium in plant defence‐signalling pathways
2006
In plant cells, the calcium ion is a ubiquitous intracellular second messenger involved in numerous signalling pathways. Variations in the cytosolic concentration of Ca2+ ([Ca2+]cyt) couple a large array of signals and responses. Here we concentrate on calcium signalling in plant defence responses, particularly on the generation of the calcium signal and downstream calcium-dependent events participating in the establishment of defence responses with special reference to calcium-binding proteins.
Crystallization and preliminary X-ray studies of oligandrin, a sterol-carrier elicitor fromPythium oligandrum
2000
Oligandrin is a 10 kDa acidic protein produced by the fungus micromycete Pythium oligandrum and is a member of the alpha-elicitin group, with sterol- and lipid-carrier properties. Oligandrin has been crystallized at 290 K using PEG 4000 as a precipitant. A cholesterol complex was obtained under the same conditions. The space group of the crystals at low temperature (100 K) is C222, with unit-cell parameters a = 94.0, b = 171.1, c = 55.3 A. Four molecules are present in the asymmetric unit. Data from the free and cholesterol-complexed forms were recorded at synchrotron sources to resolutions of 2.4 (uncomplexed) and 1.9 A (complexed), respectively.
Effect of methyl jasmonate in gene expression, and in hormonal and phenolic profiles of holm oak embryogenic lines before and after infection with Ph…
2022
The dieback syndrome affecting Quercus ilex and other oak species impels the search for tolerant plant genotypes, as well as methods of plant immunization against such infections. Elicitation treatments can be an effective strategy to activate plant defense response and embryogenic lines represent a promising tool to generate new tolerant genotypes and also to study early markers involved in defense response. The aim of the presented work was to investigate changes in gene expression, and in hormonal and phenolic profiles induced in three holm oak embryogenic lines (ELs) elicited with methyl jasmonate (MeJA) before and after infection with the oomycete Phytophthora cinnamomi, which is the m…
Induced resistance as a strategy for vineyard protection
2012
National audience; As most grown grapevine Vitis vinifera varieties are susceptible to diseases such as downy and powdery mildews, numerous treatments are required to ensure a satisfactory yield and harvest quality. However, the use of phytochemical fungicides has serious drawbacks: some of them are potentially harmful for the environment and human health and contribute to the selection of resistant pathogen strains. Nowadays, in an objective of sustainable viticulture, there is increasing societal request, political incitation and winegrower’s awareness to reduce the use of pesticides. For these reasons, alternative strategies of protection are under research. In our laboratory, we are stu…
Volatile organic compounds: a role in elicitor-induced resistance of grapevine against pathogens?
2014
International audience; As Vitis vinifera varieties are susceptible to fungal diseases, numerous chemical treatments are generally required to ensure the quantity and quality of the harvest. However, in the context of sustainable viticulture, there are increasing societal request, political incitation, and winegrowers’ awareness to reduce the use of pesticides. Among possible solutions the use of elicitors that could be included in integrated pest management or biocontrol strategies might be very promising. These bioactive compounds are able to trigger plant defences, leading to induced resistance (IR) against pathogens. Despite IR can be elicited very successfully in controlled environment…