Virus interference with trans-plasma membrane activity in infected grapevine leaves

The transmission mode of grapevine red blotch virus (GRBV, genus Grablovirus, family Geminiviridae) by Spissistilus festinus, the three-cornered alfalfa hopper, is unknown. By analogy with other members in the family Geminiviridae, we hypothesized circulative, nonpropagative transmission. Time course experiments revealed GRBV in dissected guts, hemolymph and heads with salivary glands following a 5-, 8- and 10-day exposure to infected grapevines, respectively. After a 15-day acquisition on infected grapevines and subsequent transfer on alfalfa, a non-host of GRBV, the virus titer decreased over time in adult insects, as shown by qPCR. Snap bean proved to be a feeding host of S. festinus and a pseudo-systemic host of GRBV following Agrobacterium tumefaciens-mediated delivery of an infectious clone. The virus was efficiently transmitted by S. festinus from infected snap bean plants to excised snap bean trifoliates (90%) or grapevine leaves (100%) but less efficiently from infected grapevine plants to excised grapevine leaves (10%) or snap bean trifoliates (67%). Transmission of GRBV also occurred transstadially but not via seeds. The virus titer was significantly higher in guts and hemolymph relative to heads with salivary glands, and in adults emanating from third compared with first instars that emerged on infected grapevine plants and developed on snap bean trifoliates. This study demonstrated circulative, nonpropagative transmission of GRBV by S. festinus with an extended acquisition access period compared with other viruses in the family Geminiviridae and marked differences in transmission efficiency between grapevine, the natural host, and snap bean, an alternative herbaceous host.

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Rapid analysis of stilbenes and derivatives from downy mildew-infected grapevine leaves by liquid chromatography–atmospheric pressure photoionisation mass spectrometry

Journal of Chromatography A ◽

10.1016/j.chroma.2006.01.060 ◽

2006 ◽

Vol 1112 (1-2) ◽

pp. 263-268 ◽

Cited By ~ 63

Author(s):

J. Bernard Jean-Denis ◽

Roger Pezet ◽

Raffaele Tabacchi

Keyword(s):

Mass Spectrometry ◽

Liquid Chromatography ◽

Downy Mildew ◽

Atmospheric Pressure ◽

Rapid Analysis ◽

Grapevine Leaves ◽

Infected Grapevine

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

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-05-15-0115-r ◽

2015 ◽

Vol 28 (11) ◽

pp. 1227-1236 ◽

Cited By ~ 7

Author(s):

Christelle Guillier ◽

Magdalena Gamm ◽

Géraldine Lucchi ◽

Caroline Truntzer ◽

Delphine Pecqueur ◽

...

Keyword(s):

Downy Mildew ◽

Active Compound ◽

In Silico Analysis ◽

Plasmopara Viticola ◽

Stomatal Response ◽

Protein Fractionation ◽

Biochemical Assays ◽

Grapevine Leaves ◽

Infected Grapevine ◽

Silico Analysis

Stomata remain abnormally opened and unresponsive to abscisic acid in grapevine leaves infected by downy mildew. This deregulation occurs from 3 days postinoculation 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 coupled to stomatal response and proteomic analysis allowed the identification of both plant and pathogen proteins in the active fraction obtained from IAF. Further in silico analysis and discriminant filtrations based on the comparison between predictions and experimental indications lead to the identification of two Vitis vinifera proteins as candidates for the observed stomatal deregulation.

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Changes in Carbohydrate Metabolism in Plasmopara viticola-Infected Grapevine Leaves

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-02-11-0040 ◽

2011 ◽

Vol 24 (9) ◽

pp. 1061-1073 ◽

Cited By ~ 32

Author(s):

Magdalena Gamm ◽

Marie-Claire Héloir ◽

Richard Bligny ◽

Nathalie Vaillant-Gaveau ◽

Sophie Trouvelot ◽

...

Keyword(s):

Carbohydrate Metabolism ◽

Leaf Tissue ◽

Plasmopara Viticola ◽

Invertase Activity ◽

Starch Accumulation ◽

Starch Degradation ◽

Infected Leaf ◽

Starch Metabolism ◽

Grapevine Leaves ◽

Infected Grapevine

The oomycete Plasmopara viticola is responsible for downy mildew, a severe grapevine disease. In infected grapevine leaves, we have observed an abnormal starch accumulation at the end of the dark period, suggesting modifications in starch metabolism. Therefore, several complementary approaches, including transcriptomic analyses, measurements of enzyme activities, and sugar quantification, were performed in order to investigate and to understand the effects of P. viticola infection on leaf starch and—to a larger extent—carbohydrate metabolism. Our results indicate that starch accumulation is associated with an increase in ADP-glucose pyrophosphorylase (AGPase) activity and modifications in the starch degradation pathway, especially an increased α-amylase activity. Together with these alterations in starch metabolism, we have observed an accumulation of hexoses, an increase in invertase activity, and a reduction of photosynthesis, indicating a source-to-sink transition in infected leaf tissue. Additionally, we have measured an accumulation of the disaccharide trehalose correlated to an increased trehalase gene expression and enzyme activity. Altogether, these results highlight a dramatic alteration of carbohydrate metabolism correlated with later stages of P. viticola development in leaves.

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Stomatal deregulation inPlasmopara viticola-infected grapevine leaves

New Phytologist ◽

10.1111/j.1469-8137.2006.01959.x ◽

2006 ◽

Vol 173 (4) ◽

pp. 832-840 ◽

Cited By ~ 68

Author(s):

Mathilde Allègre ◽

Xavier Daire ◽

Marie-Claire Héloir ◽

Sophie Trouvelot ◽

Laurence Mercier ◽

...

Keyword(s):

Grapevine Leaves ◽

Infected Grapevine

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Minor sequence modifications in temporin B cause drastic changes in antibacterial potency and selectivity by fundamentally altering membrane activity

10.1101/312215 ◽

2018 ◽

Cited By ~ 1

Author(s):

Giorgia Manzo ◽

Philip M. Ferguson ◽

V. Benjamin Gustilo ◽

Tam T. Bui ◽

Alex F. Drake ◽

...

Keyword(s):

Plasma Membrane ◽

Membrane Activity ◽

Gram Positive Bacteria ◽

C Terminus ◽

N Terminus ◽

Mechanism Of Interaction ◽

Minor Sequence ◽

Dynamics Simulations ◽

Effective Translation

ABSTRACTAntimicrobial peptides (AMPs) are a potential source of new molecules to counter the increase in antimicrobial resistant infections but a better understanding of their properties is required to understand their native function and for effective translation as therapeutics. Details of the mechanism of their interaction with the bacterial plasma membrane are desired since damage or penetration of this structure is considered essential for AMP activity. Relatively modest modifications to AMP primary sequence can induce substantial changes in potency and/or spectrum of activity but, hitherto, have not been predicted to substantially alter the mechanism of interaction with the bacterial plasma membrane. Here we use a combination of molecular dynamics simulations, circular dichroism, solid-state NMR and patch clamp to investigate the extent to which temporin B and its analogues can be distinguished both in vitro and in silico on the basis of their interactions with model membranes. Enhancing the hydrophobicity of the N-terminus and cationicity of the C-terminus in temporin B improves its membrane activity and potency against both Gram-negative and Gram-positive bacteria. In contrast, enhancing the cationicity of the N-terminus abrogates its ability to trigger channel conductance and renders it ineffective against Staphylococcus aureus while nevertheless enhancing its potency against Escherichia coli. Our findings suggest even closely related AMPs may target the same bacterium with fundamentally differing mechanisms of action.

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An Assay to Study Botrytis cinerea-infected Grapevine Leaves Primed with Pseudomonas fluorescens

BIO-PROTOCOL ◽

10.21769/bioprotoc.1943 ◽

2016 ◽

Vol 6 (19) ◽

Author(s):

Charlotte Gruau ◽

Patricia Trotel-Aziz ◽

Bas Verhagen ◽

Sandra Villaume ◽

Fanja Rabenoelina ◽

...

Keyword(s):

Pseudomonas Fluorescens ◽

Botrytis Cinerea ◽

Grapevine Leaves ◽

Infected Grapevine

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Heterogeneity of Size and Distribution of Intramembrane Particles in the Plasma Membrane of Yeast

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100080407 ◽

1977 ◽

Vol 35 ◽

pp. 596-597

Author(s):

E. Keyhani

Keyword(s):

Plasma Membrane ◽

Candida Utilis ◽

Synthetic Medium ◽

Freeze Fracture ◽

Translational Diffusion ◽

Yeast Cells ◽

Distilled Water ◽

Intramembrane Particles ◽

The Matrix ◽

Water Cell

The matrix of biological membranes consists of a lipid bilayer into which proteins or protein aggregates are intercalated. Freeze-fracture techni- ques permit these proteins, perhaps in association with lipids, to be visualized in the hydrophobic regions of the membrane. Thus, numerous intramembrane particles (IMP) have been found on the fracture faces of membranes from a wide variety of cells (1-3). A recognized property of IMP is their tendency to form aggregates in response to changes in experi- mental conditions (4,5), perhaps as a result of translational diffusion through the viscous plane of the membrane. The purpose of this communica- tion is to describe the distribution and size of IMP in the plasma membrane of yeast (Candida utilis).Yeast cells (ATCC 8205) were grown in synthetic medium (6), and then harvested after 16 hours of culture, and washed twice in distilled water. Cell pellets were suspended in growth medium supplemented with 30% glycerol and incubated for 30 minutes at 0°C, centrifuged, and prepared for freeze-fracture, as described earlier (2,3).

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