Search results for "Plasmopara"

Acremines A-F, novel secondary metabolites produced by an endophytic strain of Acremonium sp., isolated in grape leaves infected by Plasmopara vitico…

2005

Six novel metabolites, acremines A–F have been isolated from agar cultures of a strain of Acremonium sp. Their structures and stereochemistry were elucidated using a combination of 13C and 1H homo and heteronuclear 2D NMR experiments and X-ray analysis. Acremines A–D inhibited the germination of sporangia of Plasmopara viticola.

Identification of Acremonium isolates from grapevines and evaluation of their antagonism towards Plasmopara viticola

2015

Some endophytic fungal genera in Vitis vinifera, including Acremonium, have been reported as antagonists of Plasmopara viticola. Endophytic Acremonium isolates from an asymptomatic grapevine cultivar Inzolia from Italy were identified by morphological features and multigene phylogenies of ITS, 18S and 28S genes, and their intra-specific genomic diversity was analyzed by RAPD analysis. Culture filtrates (CFs) obtained from Acremonium isolates were tested in vitro for their inhibitory activity against the P. viticola sporangia germination. Among 94 isolates, 68 belonged to the Acremonium persicinum and 26 to the Acremonium sclerotigenum. RAPD analysis grouped the A. persicinum isolates into 1…

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…

Effect of carbendazim and physicochemical factors on the growth and ochratoxin A production of Aspergillus carbonarius isolated from grapes.

2007

Carbendazim is a systemic fungicide that is commonly used on several crops (tobacco, fruit, vegetables, cereals, etc.). This fungicide is used to control fungal infections in vineyards. It is indicated against Botrytis cinerea, Uncinula necator, Plasmopara viticola and other fungi and can be used either alone or coupled with other fungicides. However, there is a lack of in-depth studies to evaluate its effectiveness against growth of Aspergillus carbonarius isolated from grapes and OTA production. A medium based on red grape juice was used in this study. Preliminary studies were performed at 0.98 a(w) and 25 degrees C using carbendazim concentrations over a wide range (1-2000 ng/ml medium) …

A cytological and ultrastructural study on the maturation and germination of oospores of Plasmopara viticola from overwintering vine leaves.

1999

Observations on cytological and ultrastructural changes in Plasmopara viticola oospores were carried out during the overwintering period. Three types of oospores were observed. Type I, characterized by a thin inner oospore wall (IOW), large lipid globules and two nuclei, was recovered only in samples collected in October. These oospores were considered to be immature. Maturation occurred during November and involved a noticeable increase in thickness of the IOW, fusion of nuclei, formation of an ooplast and break up of large lipid globules into smaller ones (type II oospores). A few oospores (type III) showed abnormal organization with very large lipid globules and less frequently discernib…

In semi-vivo antagonism of Acremoninum byssoides towards Plasmopara viticola

2008

In previous laboratory tests the culture filtrates and the crude extracts obtained from Acremonium byssoides were shown to completely inhibit Plasmopara viticola sporangia germination. A study was thus undertaken in order to investigate on the possible inhibiting activity of the hyphomycete towards pathogenesis of the oomycete in grapevine. A. byssoides was cultivated on malt-extract agar (MEA) to obtain pure colonies and on maltextract broth (MEB) to obtain culture filtrate and crude extract. Healthy leaves of grapevine were put in Petri dishes containing sporangia suspended in: deionized sterile water, malt-extract broth, dimethylsulfoxide (DMSO), culture filtrate, crude extract and a sus…

Impact of Plasmopara viticola on starch metabolism and stomachal functions in grapevine leaves

2011

The grapevine downy mildew affects leaves and young berries and can affect the harvest quality and quantity. The causal agent is the obligate biotroph oomycete Plasmopara viticola that induces severe physiological alterations in infected leaves. One is the abnormal accumulation of starch in oil spots, the characteristic symptoms of the disease. Another is a deregulation of stomatal movements. Stomata, natural openings on the leaf surface allowing gas exchanges between the plant and the atmosphere, stay abnormally open during the night and do no longer close upon water stress or ABA treatment in infected leaves. This thesis is divided into two chapters that aim to i) explain the origin and m…

Sull'interazione tra Acremonium sp., Vitis vinifera e Plasmopara viticola.

2002

Antimicrobial Activity of Resveratrol Analogues

2014

Stilbenes, especially resveratrol and its derivatives, have become famous for their positive effects on a wide range of medical disorders, as indicated by a huge number of published studies. A less investigated area of research is their antimicrobial properties. A series of 13 trans-resveratrol analogues was synthesized via Wittig or Heck reactions, and their antimicrobial activity assessed on two different grapevine pathogens responsible for severe diseases in the vineyard. The entire series, together with resveratrol, was first evaluated on the zoospore mobility and sporulation level of Plasmopara viticola (the oomycete responsible for downy mildew). Stilbenes displayed a spectrum of acti…

Toward the Identification of Two Glycoproteins Involved in the Stomatal Deregulation of Downy Mildew–Infected Grapevine Leaves

2015

SPE Pôle IPM UB; International audience; Stomata remain abnormally opened and unresponsive to abscisic acid in grapevine leaves infected by downy mildew. This deregulation occurs from 3 days post inoculation and increases concomitantly with leaf colonization by the pathogen. Using epidermal peels, we demonstrated that the active compound involved in this deregulation is located in the apoplast. Biochemical assays showed that the active compound present in the apoplastic fluids isolated from Plasmopara viticola infected grapevine leaves (IAF) is a CysCys bridge-independent, thermostable and glycosylated protein. Fractionation guided assays based on chromatography / stomatal response and prot…