Institute des science en Production Vegetale IPV

Nyon, Switzerland

Institute des science en Production Vegetale IPV

Nyon, Switzerland
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Zufferey V.,Institute des science en Production Vegetale IPV | Murisier F.,Institute des science en Production Vegetale IPV | Belcher S.,Institute des science en Denrees Alimentaires IDA | Lorenzini F.,Institute des science en Denrees Alimentaires IDA | And 3 more authors.
Vitis - Journal of Grapevine Research | Year: 2015

Seasonal patterns of total organic nitrogen (N) and total non-structural carbohydrate (TNC) concentrations in relation to the leaf-fruit ratio (source-sink) were measured over three years at different grapevine phenological stages in one- and two-year-old canes, trunks and roots of the cultivar 'Chasselas' (Vitis vinifera L.). The highest N and TNC concentrations were observed during the period from dormancy until budbreak. A decrease in the N and TNC reserves was measured in the different organs (canes, trunks and roots) from budbreak, reaching minimum values around flowering, except for the N concentration in the roots, which was lowest during the period between bunch closure and veraison. N storage was highest in the roots and occurred from veraison until leaf fall. The N concentration in the trunks and canes represented approximately half of that measured in the roots. TNCs accumulated preferentially in the roots and also in the trunks and canes during the growing season. The leaf area per vine (or canopy height) and yield both influenced the N concentration in the roots. High yield and low leaf area per vine decreased the N concentration in the roots. The leaf-fruit ratio, expressed as the "light-exposed leaf area per kg fruit", substantially influenced the N and TNC concentrations in the roots at harvest. The highest N and TNC concentrations in the roots were obtained when the leaf-fruit ratio approached 2.0 m2 of light-exposed leaf area per kg fruit. © The author(s).


Hofstetter V.,Institute des science en production vegetale IPV | Redhead S.A.,Eastern Cereal and Oilseed Research Center | Kauff F.,University of Kaiserslautern | Moncalvo J.-M.,Royal Ontario Museum | Vilgalys R.,University of Tennessee at Knoxville
Cryptogamie, Mycologie | Year: 2014

We explored evolutionary relationships within the Lyophyllaceae by combining sequence data from six loci. The most likely phylogram led us to reconsider the Lyophyllaceae classification with the recognition of two new genera (Myochromella and Sagaranella) based on ecological and/or morphological distinctiveness. Lyophyllaceae are ecologically highly diversified and our phylogeny suggests that four to five ecological transitions from free-living to parasitic or mutualistic lifestyles have occurred within the family. Due to moderate phylogenetic support recovered for several relationships within that clade and due to the uncertainty about the ecological strategy adopted by five of the sampled species, three out of these transitions could be unequivocally reconstructed suggesting that saprotrophy is plesiomorphic for Lyophyllaceae. Significant differences in rates of molecular evolution were detected among taxa. These differences are not associated with ecological transitions throughout the Lyophyllaceae, however, within each of the major clades identified in the family, taxa of different ecological strategies show an overall tendency to evolve at different speeds at the molecular level. © 2014 Adac. Tous droits réservés.


Pagay V.,Cornell University | Pagay V.,University of Adelaide | Zufferey V.,Institute des science en Production Vegetale IPV | Lakso A.N.,Cornell University
Functional Plant Biology | Year: 2016

Recent climatic trends of higher average temperatures and erratic precipitation patterns are resulting in decreased soil moisture availability and, consequently, periods of water stress. We studied the effects of seasonal water stress on grapevine (Vitis vinifera L. cv. Riesling grafted onto 101-14 (Vitis riparia Michx.×Vitis rupestris Scheele) rootstock) shoot growth, leaf gas exchange, xylem morphology and hydraulic performance in the cool-climate Finger Lakes region of New York. A plastic rain exclusion tarp was installed on the vineyard floor to create a soil moisture deficit and consequently induce vine water stress. Weekly measurements of predawn leaf and midday stem water potentials (Ψmd) were made, and two contrasting shoot length classes, long (length >2.0m) and short (length <1.0m), were monitored. Growth of both long and short shoots was positively correlated with Ψmd but no difference in water status was found between the two. Compared with rain-fed vines, water-stressed vines had lower photosynthesis and stomatal conductance later in the season when Ψmd dropped below -1.2MPa. Long shoots had three-fold higher xylem-specific hydraulic conductivity values than short shoots. Long shoots experiencing water stress were less vulnerable to xylem cavitation than shorter shoots even though they had more large-diameter vessels. The lower vulnerability to cavitation of long shoots may be attributed to less xylem intervessel pitting being found in long shoots, consistent with the air-seeding hypothesis, and suggests that a hydraulic advantage enables them to maintain superior growth and productivity under water stress.


PubMed | University of Western Sydney, University of Tasmania, Institute des science en production vegetale IPV, University of Ulm and 2 more.
Type: Journal Article | Journal: Plant, cell & environment | Year: 2016

Plants can be highly segmented organisms with an independently redundant design of organs. In the context of plant hydraulics, leaves may be less embolism resistant than stems, allowing hydraulic failure to be restricted to distal organs that can be readily replaced. We quantified drought-induced embolism in needles and stems of Pinus pinaster using high-resolution computed tomography (HRCT). HRCT observations of needles were compared with the rehydration kinetics method to estimate the contribution of extra-xylary pathways to declining hydraulic conductance. High-resolution computed tomography images indicated that the pressure inducing 50% of embolized tracheids was similar between needle and stem xylem (P50 needle xylem =-3.62MPa, P50 stem xylem =-3.88MPa). Tracheids in both organs showed no difference in torus overlap of bordered pits. However, estimations of the pressure inducing 50% loss of hydraulic conductance at the whole needle level by the rehydration kinetics method were significantly higher (P50 needle =-1.71MPa) than P50 needle xylem derived from HRCT. The vulnerability segmentation hypothesis appears to be valid only when considering hydraulic failure at the entire needle level, including extra-xylary pathways. Our findings suggest that native embolism in needles is limited and highlight the importance of imaging techniques for vulnerability curves.


Marti G.,University of Geneva | Marti G.,Toulouse 1 University Capitole | Schnee S.,Institute des science en Production Vegetale IPV | Andrey Y.,University of Geneva | And 4 more authors.
Molecules | Year: 2014

UV-C radiation is known to induce metabolic modifications in plants, particularly to secondary metabolite biosynthesis. To assess these modifications from a global and untargeted perspective, the effects of the UV-C radiation of the leaves of three different model plant species, Cissus antarctica Vent. (Vitaceae), Vitis vinifera L. (Vitaceae) and Cannabis sativa L. (Cannabaceae), were evaluated by an LC-HRMS-based metabolomic approach. The approach enabled the detection of significant metabolite modifications in the three species studied. For all species, clear modifications of phenylpropanoid metabolism were detected that led to an increased level of stilbene derivatives. Interestingly, resveratrol and piceid levels were strongly induced by the UV-C treatment of C. antarctica leaves. In contrast, both flavonoids and stilbene polymers were upregulated in UV-C-treated Vitis leaves. In Cannabis, important changes in cinnamic acid amides and stilbene-related compounds were also detected. Overall, our results highlighted phytoalexin induction upon UV-C radiation. To evaluate whether UV-C stress radiation could enhance the biosynthesis of bioactive compounds, the antioxidant activity of extracts from control and UV-C-treated leaves was measured. The results showed increased antioxidant activity in UV-C-treated V. vinifera extracts. © Molecules 2014.


PubMed | Institute des science en Production Vegetale IPV and University of Geneva
Type: Journal Article | Journal: Molecules (Basel, Switzerland) | Year: 2014

UV-C radiation is known to induce metabolic modifications in plants, particularly to secondary metabolite biosynthesis. To assess these modifications from a global and untargeted perspective, the effects of the UV-C radiation of the leaves of three different model plant species, Cissus antarctica Vent. (Vitaceae), Vitis vinifera L. (Vitaceae) and Cannabis sativa L. (Cannabaceae), were evaluated by an LC-HRMS-based metabolomic approach. The approach enabled the detection of significant metabolite modifications in the three species studied. For all species, clear modifications of phenylpropanoid metabolism were detected that led to an increased level of stilbene derivatives. Interestingly, resveratrol and piceid levels were strongly induced by the UV-C treatment of C. antarctica leaves. In contrast, both flavonoids and stilbene polymers were upregulated in UV-C-treated Vitis leaves. In Cannabis, important changes in cinnamic acid amides and stilbene-related compounds were also detected. Overall, our results highlighted phytoalexin induction upon UV-C radiation. To evaluate whether UV-C stress radiation could enhance the biosynthesis of bioactive compounds, the antioxidant activity of extracts from control and UV-C-treated leaves was measured. The results showed increased antioxidant activity in UV-C-treated V. vinifera extracts.


Gindro K.,Institute des science en Production Vegetale IPV | Lecoultre N.,Institute des science en Production Vegetale IPV | Molino L.,Institute des science en Production Vegetale IPV | De Joffrey J.-P.,Institute des science en Production Vegetale IPV | And 5 more authors.
Journal International des Sciences de la Vigne et du Vin | Year: 2014

Aims: The development of a rapid and reliable direct PCR method to detect fungal propagules in grapevine tissues without prior DNA purification steps, and illustration of its potential use with different examples. Methods and results : Different grapevine samples crushed in the presence of polyvinylpolypyrrolidone (PVPP) were used as templates for direct PCR amplification with primers specific for Erysiphe necator, Plasmopara viticola, Botrytis cinerea and Vitis vinifera. Sequencing of the PCR products confirmed the specificity of the amplifications. The sensitivity tested using conidia/sporangia dilution series was high, ranging from five sporangia for P. viticola to one conidium for E. necator. The potential of this technique is illustrated through the study of four epidemiological questions. Fungal propagules were observed in dormant buds using microscopy, but the responsible species could not be identified. Direct PCR revealed the presence of E. necator and B. cinerea in 29 % and 65 % of the buds, respectively. Downy mildew could be detected in asymptomatic leaves sampled in fields after potentially infectious events. In bunch, microscopic analysis of rachis sections showed the presence of hyphae growing in the green tissue. Direct PCR identified the presence of P. viticola. Conclusion : A direct PCR method without DNA purification was demonstrated to be a simple and reliable method for the detection and identification of fungal pathogens in grapevine tissues. This method, together with microscopy, is a very interesting tool that can be used to study various epidemiological problems in the grapevine, including important unanswered questions such as the route of infection that leads to brown rot caused by downy mildew. Significance and impact of the study: Direct PCR was shown to be a simple and versatile technique for the study of epidemiological questions in the grapevine. This technique could be extended to other pathosystems with minor adaptations. © Vigne et Vin Publications Internationales (Bordeaux, France).


Gill E.D.,Institute des science en Production Vegetale IPV | Schaerer S.,Institute des science en Production Vegetale IPV | Dupuis B.,Institute des science en Production Vegetale IPV
European Journal of Plant Pathology | Year: 2014

Stem rot symptoms caused by pectinolytic bacteria of Genus Pectobacterium and Genus Dickeya, which are commonly referred to as blackleg, strongly impact the quality of seed potato production in most European countries. Several biotic and abiotic factors, such as cultivar susceptibility, isolate aggressiveness, mother tuber infection density and a wide range of soil-related and climatic factors have been identified in the literature as having an effect on blackleg development. The aim of this study was to identify which biotic and/or abiotic factors are most critical to the development of blackleg in the field. In Switzerland, the predominant species have belonged to Genus Dickeya as far back as 1992, which is why this study only investigates blackleg symptoms induced by Dickeya isolates. Seven field trials, in which inoculated tubers were planted, were conducted during a 3-year period and the number of blackleg-diseased plants was counted. Multiple regression analysis was used in order to determine the factors that had the greatest impact on two different variables: (i) periods between emergence of the plant and disease outbreak and (ii) overall blackleg incidence throughout the growing season. The results of this analysis have revealed that environmental factors, such as evapotranspiration and soil moisture, explain about half of the variability in the number of days before disease outbreak, and the total number of diseased plants is widely dependent upon cultivar susceptibility and isolate aggressiveness. © 2014 Koninklijke Nederlandse Planteziektenkundige Vereniging.


Zufferey V.,Institute des science en Production Vegetale IPV | Spring J.-L.,Institute des science en Production Vegetale IPV | Voinesco F.,Institute des science en Production Vegetale IPV | Viret O.,Institute des science en Production Vegetale IPV | Gindro K.,Institute des science en Production Vegetale IPV
Journal International des Sciences de la Vigne et du Vin | Year: 2015

Aims : The current work aims to study berry shrivel in grapes (a grape-ripening disorder) in relation to vine water status and climatic conditions using physiological and histological approaches. Methods and results : Measurements of rachis hydraulic conductance on grapevine clusters (Vitis vinifera L.) and observations of the vascular tissues (xylem and phloem) using transmission electron microscopy were conducted on rachises from healthy clusters and clusters having berry shrivel (BS) symptoms during the season. BS intensity was largely dependent on the vine water status : BS was greater in vines without water stress than in vines with moderate to high water stress around veraison time. Preliminary results showed that rachis hydraulic conductance declined sharply after veraison but remained slightly higher in healthy clusters in comparison with clusters presenting BS symptoms. An important degradation of the primary phloem was observed in the rachises of BS clusters, with the appearance of hard, nonfunctional liber (secondary phloem) and a disorganization of the cell content in the phloem tissue. An alteration of the primary xylem was also observed in the middle of the rachis and in the secondary rachis ramifications. Conclusion : These results suggest that the decrease in sugar and water accumulation in BS berries would primarily be associated with a decline in rachis phloem functionality. Significance and impact of the study : The management of the vine water status plays a key role in berry shrivel development. © 2015 Vigne et Vin Publications Internationales.


Zufferey V.,Institute des science en Production Vegetale IPV
Vitis - Journal of Grapevine Research | Year: 2016

The leaf respiration (RD) of grapevine (Vitis vinifera 'Chasselas') was measured under field conditions during the growing season in leaves of different physiological ages in relation to the temperature and plant water status. RD increased with the temperature and was particularly high in young growing leaves on primary and lateral shoots. The RD response to the temperature evolved over the season according to the type and age of the leaves and their phenology. Leaf aging (senescence) induced a decrease in RD at the end of the season. At constant temperatures (20 °C), the highest RD rates were measured during the rapid plant growth phase (the Q10 values were also the highest), and they progressively decreased to reach their lowest rates at the end of the growing season. The lowest RD values were measured on leaves that were inserted opposite the clusters of primary shoots at any period during the season. Water stress led to a reduction in RD, especially when the leaf temperature was above 20 °C. The nocturnal RD evolution showed that the RD rates were greatest at nightfall when the nocturnal temperatures were still high and leaf carbohydrate availability was at its highest; the rates gradually decreased to reach the lowest RD values just before dawn. © The author(s).

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