Search results for "Plant biology"
showing 10 items of 1494 documents
Mediation of Elicitin Activity on Tobacco Is Assumed by Elicitin-Sterol Complexes
2001
Elicitins secreted by phytopathogenic Phytophthora spp. are proteinaceous elicitors of plant defense mechanisms and were demonstrated to load, carry, and transfer sterols between membranes. The link between elicitor and sterol-loading properties was assessed with the use of site-directed mutagenesis of the 47 and 87 cryptogein tyrosine residues, postulated to be involved in sterol binding. Mutated cryptogeins were tested for their ability to load sterols, bind to plasma membrane putative receptors, and trigger biological responses. For each mutated elicitin, the chemical characterization of the corresponding complexes with stigmasterol (1:1 stoichiometry) demonstrated their full functionali…
β-Aminobutyric Acid Primes an NADPH Oxidase–Dependent Reactive Oxygen Species Production During Grapevine-Triggered Immunity
2010
International audience; The molecular mechanisms underlying the process of priming are poorly understood. In the present study, we investigated the early signaling events triggered by β-aminobutyric acid (BABA), a well-known priming-mediated plant resistance inducer. Our results indicate that, in contrast to oligogalacturonides (OG), BABA does not elicit typical defense-related early signaling events nor defense-gene expression in grapevine. However, in OG-elicited cells pretreated with BABA, production of reactive oxygen species (ROS) and expression of the respiratory-burst oxidase homolog RbohD gene were primed. In response to the causal agent of downy mildew Plasmopara viticola, a strong…
Lotus tenuis x L. corniculatus interspecific hybridization as a means to breed bloat-safe pastures and gain insight into the genetic control of proan…
2014
Background: Proanthocyanidins (PAs) are secondary metabolites that strongly affect plant quality traits. The concentration and the structure of these metabolites influence the palatability and nutritional value of forage legumes. Hence, modulating PAs in the leaves of forage legumes is of paramount relevance for forage breeders worldwide. The lack of genetic variation in the leaf PA trait within the most important forage species and the difficulties in engineering this pathway via the ectopic expression of regulatory genes, prompted us to pursue alternative strategies to enhance this trait in forage legumes of agronomic interest. The Lotus genus includes forage species which accumulate PAs …
Competitive interaction of three peroxidizing herbicides with the binding of 3H acifluorfen to corn etioplast membranes
1990
AbstractThe specific binding of the herbicide acifluorfen 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid to corn etioplast membranes is competitively inhibited by protoporphyrinogen IX, the substrate of protoporphyrinogen oxidase. Three other peroxidizing molecules, oxadiazon [5-ter-butyl-3-(2,4-dichloro-5-isopropoxyphenyl)-1,3,4-oxadiazol-2-one], LS 82556 [(S)3-N-(methylbenzyl)carbamoyl-5-propionyl-2,6-lutidine], and M&B 39279 [5-amino-4-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)pyrazol], also compete with acifluorfen for its binding site. The four herbicides thus bind to the same site, or to closely located sites, on the enzyme protoporphyrinogen oxidase.
A β-1,3 Glucan Sulfate Induces Resistance in Grapevine against Plasmopara viticola Through Priming of Defense Responses, Including HR-like Cell Death
2008
Sulfated laminarin (PS3) has been shown previously to be an elicitor of plant defense reactions in tobacco and Arabidopsis and to induce protection against tobacco mosaic virus. Here, we have demonstrated the efficiency of PS3 in protecting a susceptible grapevine cultivar (Vitis vinifera cv. Marselan) against downy mildew (Plasmopara viticola) under glasshouse conditions. This induced resistance was associated with potentiated H2O2 production at the infection sites, upregulation of defense-related genes, callose and phenol depositions, and hypersensitive response-like cell death. Interestingly, similar responses were observed following P. viticola inoculation in a tolerant grapevine hybri…
Fragmentation-related patterns of genetic differentiation in pedunculate oak (Quercus robur) at two hierarchical scales
2016
Populations at species' range margins are expected to show lower genetic diversity than populations at the core of the range. Yet, long-lived, widespread tree species are expected to be resistant to genetic impoverishment, thus showing comparatively high genetic diversity within populations and low differentiation among populations. Here, we study the distribution of genetic variation in the pedunculate oak (Quercus robur L.) at its range margin in Finland at two hierarchical scales using 15 microsatellite loci. At a regional scale, we compared variation within versus among three oak populations. At a landscape scale, we examined genetic structuring within one of these populations, growing …
Comparative study on the quality characteristics of some Egyptian mango cultivars used for food processing
2016
This study aims to investigate the physical, chemical, rheological and sensorial properties of six common mango (Mangifera indica) cultivars in Egypt. These common cultivars were Alfonse, Sedeka, Awis, Sinara, Sukari and Zibdia. Weights of mango fruits ranged between 246.6 and 549.2 g. The highest significant value of sphericity was in Alfonse fruits (0.82), whereas the lowest value was 0.58 in Sinara fruits. The highest firmness value was 29.51 N in Sedeka fruits. The highest elasticity was 1.16 N/mm for Sukari fruits. The significantly color intensity chroma was recorded by Sinara, whereas the highest total color index (ΔE) was 88.41 for Sedeka mango cultivar. The significantly lowest pH …
Unravelling the modus operandi of phytosiderophores during zinc uptake in rice: the importance of geochemical gradients and accurate stability consta…
2020
Abstract Micronutrient deficiencies threaten global food production. Attempts to biofortify crops rely on a clear understanding of micronutrient uptake processes. Zinc deficiency in rice is a serious problem. One of the pathways proposed for the transfer of zinc from soils into rice plants involves deoxymugineic acid (DMA), a phytosiderophore. The idea that phytosiderophores play a wider role in nutrition of Poaceae beyond iron is well established. However, key mechanistic details of the DMA-assisted zinc uptake pathway in rice remain uncertain. In particular, questions surround the form in which zinc from DMA is taken up [i.e. as free aqueous Zn(II) or as Zn(II)–DMA complexes] and the role…
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.