Search results for "phytoalexins"

Effects of resveratrol on the ultrastructure of Botrytis cinerea conidia and biological significance in plant/pathogen interactions

2012

International audience; Many roles have been ascribed to stilbenes, namely as antimicrobial, deterrent or repellent compounds in plants, protecting them from attacks by fungi, bacteria, nematodes or herbivores, acting both as constitutive and active defense (phytoalexin) compounds. More recently, stilbenes (especially resveratrol and its derivatives) were acclaimed for their wondrous effects and wide range of purported healing and preventive powers as cardioprotective, antitumor, neuroprotective and antioxidant agents. Although there is a huge number of works concerning the role of resveratrol in human health, reports on the antifungal activity of this compound are still scarce. This study …

Soybean and casein hydrolysates induce grapevine immune responses and resistance against Plasmopara viticola

2014

International audience; Plasmopara viticola, the causal agent of grapevine downy mildew, is one of the most devastating grape pathogen in Europe and North America. Although phytochemicals are used to control pathogen infections, the appearance of resistant strains and the concern for possible adverse effects on environment and human health are increasing the search for alternative strategies. In the present investigation, we successfully tested two protein hydrolysates from soybean (soy) and casein (cas) to trigger grapevine resistance against P. viticola. On Vitis vinifera cv. Marselan plants, the application of soy and cas reduced the infected leaf surface by 76 and 63%, as compared to th…

Analysis of the Molecular Dialogue Between Gray Mold (Botrytis cinerea) and Grapevine (Vitis vinifera) Reveals a Clear Shift in Defense Mechanisms Du…

2015

Mature grapevine berries at the harvesting stage (MB) are very susceptible to the gray mold fungus Botrytis cinerea, while veraison berries (VB) are not. We conducted simultaneous microscopic and transcriptomic analyses of the pathogen and the host to investigate the infection process developed by B. cinerea on MB versus VB, and the plant defense mechanisms deployed to stop the fungus spreading. On the pathogen side, our genome-wide transcriptomic data revealed that B. cinerea genes upregulated during infection of MB are enriched in functional categories related to necrotrophy, such as degradation of the plant cell wall, proteolysis, membrane transport, reactive oxygen species (ROS) genera…

Resveratrol, a polyphenolic phytoalexin present in red wine, enhances expression and activity of endothelial nitric oxide synthase.

2002

Background— Estrogens can upregulate endothelial nitric oxide synthase (eNOS) in human endothelial cells by increasing eNOS promoter activity and enhancing the binding activity of the transcription factor Sp1. Resveratrol, a polyphenolic phytoalexin found in grapes and wine, has been reported to act as an agonist at the estrogen receptor. Therefore, we tested the effect of this putative phytoestrogen on eNOS expression in human endothelial cells. Methods and Results— Incubation of human umbilical vein endothelial cells (HUVEC) and HUVEC-derived EA.hy 926 cells with resveratrol for 24 to 72 hours upregulated eNOS mRNA expression in a time- and concentration-dependent manner (up to 2.8-fold)…

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.

Changes in the Phytoalexin Content of Various Vitis Spp. in Response to Ultraviolet C Elicitation

1999

The phytoalexin production potential of three American Vitis species and that of three cultivars of Vitis vinifera were evaluated in response to UV-C irradiation. Time course changes in resveratrol, piceid, epsilon-viniferin, and pterostilbene contents were studied within 3 days after a short UV-C irradiation. Results show that the two major stilbenes accumulated as a response to UV-C elicitation are resveratrol and epsilon-viniferin, a resveratrol dehydrodimer, the concentration of both compounds usually reaching quantities >100 microgram/g of fresh weight. In contrast, piceid and pterostilbene were constantly produced in low quantities. Owing to the results obtained, the role of stilbene …

Comment stimuler l’immunité de la vigne avec des éliciteurs

2013

Natural oxygenation of Champagne wine during ageing on lees: A metabolomics picture of hormesis

2016

International audience; The oxygenation of Champagne wine after 4 and 6 years of aging on lees in bottle was investigated by FTICR-MS and UPLC-Q-TOF-MS. Three levels of permeability were considered for the stoppers, ranging from 0.2 to 1.8 mg/L/year of oxygen transfer rate. Our results confirmed a good repeatability of ultrahigh resolution FTICR-MS, both in terms of m/z and coefficient of variation of peak intensities among biological replicates. Vintages appeared to be the most discriminated features, and metabolite annotations suggested that the oldest wines (2006) were characterized by a higher sensitivity towards oxygenation. Within each vintage, the oxygenation mechanisms appeared to b…