References of "du Jardin, Patrick"
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See detailReview: Implementing biostimulants and biocontrol strategies in the agroecological management of cultivated ecosystems
Le Mire, Géraldine ULg; Nguyen, Minh ULg; Fassotte, Bérénice ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (in press)

This review describes the current methods for exploiting and applying plant growth-promoting rhizbacteria (PGPR), elicitors and semiochemical products in contemporary agricultural systems. The future of ... [more ▼]

This review describes the current methods for exploiting and applying plant growth-promoting rhizbacteria (PGPR), elicitors and semiochemical products in contemporary agricultural systems. The future of these biostimulant and biocontrol tools for the sustainable management of agricultural practices is also discussed. Special attention is given to the formulation of these products and the network of interactions taking place in cultivated ecosystems [less ▲]

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See detailHow do Rhizobacterial Volatiles Influence Root System Architecture, Biomass Production and Allocation of the Model Grass Brachypodium distachyon?
Delaplace, Pierre ULg; Ormeño - Lafuente, Elena; Nguyen, Minh ULg et al

Conference (2016, January 12)

Plant growth-promoting rhizobacteria are increasingly considered as a complement of conventional inputs in agricultural systems. Their effects on their host plants are diverse and include volatile ... [more ▼]

Plant growth-promoting rhizobacteria are increasingly considered as a complement of conventional inputs in agricultural systems. Their effects on their host plants are diverse and include volatile-mediated growth enhancement. The present study aims at assessing the effects of bacterial volatile production on the biomass production and the root system architecture of Brachypodium distachyon (L.) Beauv. (line Bd-21). An in vitro experimental set-up allowing plant-bacteria interaction through the gaseous phase without any physical contact was used to screen 19 bacterial strains for their growth promotion ability over a 10-day cocultivation period. Using principal component analysis followed by hierarchical clustering and two-way analysis of variance, five groups of bacteria were defined and characterized based on their combined influence on biomass production and root system architecture. The observed effects range from unchanged to highly increased biomass production coupled with increased root length and branching. Primary root length was only increased by the volatile compounds emitted by Enterobacter cloacae JM22 and Bacillus pumilus T4. Overall, the most significant results were obtained with Bacillus subtilis GB03 which induced a 81% increase in total biomass and enhanced total root length, total secondary root length and total adventitious root length by 88, 196 and 473% respectively. The analysis of the emission kinetics of bacterial volatile organic compounds is underway and should lead to the identification of volatile compounds candidates responsible for the observed growth promotion effects. Taking into account the inherent characteristics of our in vitro system, the next experimental steps are identified and discussed from a fundamental and applied viewpoint. [less ▲]

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See detailarchiDART: an R package for the automated computation of plant root architectural traits
Delory, Benjamin ULg; Baudson, Caroline ULg; Brostaux, Yves ULg et al

in Plant and Soil (2016), 398(1), 351-365

Background and Aims In order to analyse root system architectures (RSAs) from captured images, a variety of manual (e.g. Data Analysis of Root Tracings, DART), semi-automated and fully automated software ... [more ▼]

Background and Aims In order to analyse root system architectures (RSAs) from captured images, a variety of manual (e.g. Data Analysis of Root Tracings, DART), semi-automated and fully automated software packages have been developed. These tools offer complementary approaches to study RSAs and the use of the Root System Markup Language (RSML) to store RSA data makes the comparison of measurements obtained with different (semi-) automated root imaging platforms easier. The throughput of the data analysis process using exported RSA data, however, should benefit greatly from batch analysis in a generic data analysis environment (R software). Methods We developed an R package (archiDART) with five functions. It computes global RSA traits, root growth rates, root growth directions and trajectories, and lateral root distribution from DART-generated and/or RSML files. It also has specific plotting functions designed to visualise the dynamics of root system growth. Results The results demonstrated the ability of the package’s functions to compute relevant traits for three contrasted RSAs (Brachypodium distachyon [L.] P. Beauv., Hevea brasiliensis Müll. Arg. and Solanum lycopersicum L.). Conclusions This work extends the DART software package and other image analysis tools supporting the RSML format, enabling users to easily calculate a number of RSA traits in a generic data analysis environment. [less ▲]

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See detailarchiDART: Plant Root System Architecture Analysis Using DART and RSML Files
Delory, Benjamin ULg; Baudson, Caroline ULg; Brostaux, Yves ULg et al

Computer development (2015)

Analysis of complex plant root system architectures (RSA) using the output files created by Data Analysis of Root Tracings (DART), an open-access software dedicated to the study of plant root architecture ... [more ▼]

Analysis of complex plant root system architectures (RSA) using the output files created by Data Analysis of Root Tracings (DART), an open-access software dedicated to the study of plant root architecture and development across time series (Le Bot et al (2010) DART: a software to analyse root system architecture and development from captured images, Plant and Soil, DOI: 10.1007/s11104-009-0005-2), and RSA data encoded with the Root System Markup Language (RSML) (Lobet et al (2015) Root System Markup Language: toward a unified root architecture description language, Plant Physiology, DOI: 10.1104/pp.114.253625). More information can be found in Delory et al (2015) archiDART: an R package for the automated computation of plant root architectural traits, Plant and Soil, DOI: 10.1007/s11104-015-2673-4. [less ▲]

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See detailTowards new bioherbicides derived from barley root allelochemicals
Bouhaouel, Imen ULg; Gfeller, Aurélie; Fauconnier, Marie-Laure ULg et al

Conference (2015, October 09)

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See detailInfluence of rhizobacterial volatiles on the root system architecture and the production and allocation of biomass in the model grass Brachypodium distachyon (L.) P. Beauv.
Delaplace, Pierre ULg; Delory, Benjamin ULg; Baudson, Caroline ULg et al

in BMC Plant Biology (2015), 15(195),

Background Plant growth-promoting rhizobacteria are increasingly being seen as a way of complementing conventional inputs in agricultural systems. The effects on their host plants are diverse and include ... [more ▼]

Background Plant growth-promoting rhizobacteria are increasingly being seen as a way of complementing conventional inputs in agricultural systems. The effects on their host plants are diverse and include volatile-mediated growth enhancement. This study sought to assess the effects of bacterial volatiles on the biomass production and root system architecture of the model grass Brachypodium distachyon (L.) Beauv. Results An in vitro experiment allowing plant-bacteria interaction throughout the gaseous phase without any physical contact was used to screen 19 bacterial strains for their growth-promotion ability over a 10-day co-cultivation period. Five groups of bacteria were defined and characterised based on their combined influence on biomass production and root system architecture. The observed effects ranged from unchanged to greatly increased biomass production coupled with increased root length and branching. Primary root length was increased only by the volatile compounds emitted by Enterobacter cloacae JM22 and Bacillus pumilus T4. Overall, the most significant results were obtained with Bacillus subtilis GB03, which induced an 81% increase in total biomass, as well as enhancing total root length, total secondary root length and total adventitious root length by 88.5, 201.5 and 474.5%, respectively. Conclusions This study is the first report on bacterial volatile-mediated growth promotion of a grass plant. Contrasting modulations of biomass production coupled with changes in root system architecture were observed. Most of the strains that increased total plant biomass also modulated adventitious root growth. Under our screening conditions, total biomass production was strongly correlated with the length and branching of the root system components, except for primary root length. An analysis of the emission kinetics of the bacterial volatile compounds is being undertaken and should lead to the identification of the compounds responsible for the observed growth-promotion effects. Within the context of the inherent characteristics of our in vitro system, this paper identifies the next critical experimental steps and discusses them from both a fundamental and an applied perspective. [less ▲]

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See detailRhizobacterial volatiles influence root system architecture, biomass production and allocation of the model grass Brachypodium distachyon (L.) P. Beauv.
Delaplace, Pierre ULg; Ormeño-Lafuente, Elena; Delory, Benjamin ULg et al

Conference (2015, June 18)

Plant growth-promoting rhizobacteria are increasingly considered as a complement of conventional inputs in agricultural systems. Their effects on their host plants are diverse and include volatile ... [more ▼]

Plant growth-promoting rhizobacteria are increasingly considered as a complement of conventional inputs in agricultural systems. Their effects on their host plants are diverse and include volatile-mediated growth enhancement. The present study aims at assessing the effects of bacterial volatile production on the biomass production and the root system architecture of Brachypodium distachyon (L.) Beauv. (line Bd-21). An in vitro experimental set-up allowing plant-bacteria interaction through the gaseous phase without any physical contact was used to screen 19 bacterial strains for their growth promotion ability over a 10-day cocultivation period. Using principal component analysis followed by hierarchical clustering and two-way analysis of variance, five groups of bacteria were defined and characterized based on their combined influence on biomass production and root system architecture. The observed effects range from unchanged to highly increased biomass production coupled with increased root length and branching. Primary root length was only increased by the volatile compounds emitted by Enterobacter cloacae JM22 and Bacillus pumilus T4. Overall, the most significant results were obtained with Bacillus subtilis GB03 which induced a 81% increase in total biomass and enhanced total root length, total secondary root length and total adventitious root length by 88, 196 and 473% respectively. The analysis of the emission kinetics of bacterial volatile organic compounds is underway and should lead to the identification of volatile compounds candidates responsible for the observed growth promotion effects. Taking into account the inherent characteristics of our in vitro system, the next experimental steps are identified and discussed from a fundamental and applied viewpoint. [less ▲]

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See detailThe CROSTVOC project – an integrated approach to study the effect of stress on BVOC exchange between agricultural crops and grassland ecosystems and the atmosphere
Amelynck, Crist; Heinesch, Bernard ULg; Aubinet, Marc ULg et al

in Geophysical Research Abstracts (2015, April), 17

Global changes in atmospheric composition and climate are expected to affect BVOC exchange between terrestrial vegetation and the atmosphere through changes in the drivers of constitutive BVOC emissions ... [more ▼]

Global changes in atmospheric composition and climate are expected to affect BVOC exchange between terrestrial vegetation and the atmosphere through changes in the drivers of constitutive BVOC emissions and by increases in frequency and intensity of biotic or abiotic stress episodes. Indeed, several studies indicate changes in the emission patterns of constitutive BVOCs and emission of stress-induced BVOCs following heat, drought and oxidative stress, amongst others. Relating changes in BVOC emissions to the occurrence of one or multiple stressors in natural environmental conditions is not straightforward and only few field studies have dealt with it, especially for agricultural crop and grassland ecosystems. The CROSTVOC project aims to contribute in filling this knowledge gap in three ways. Firstly, it aims at performing long-term BVOC emission field measurements from maize (Zea mays L.) and wheat (Triticum aestivum L.), two important crop species on the global scale, and from grassland. This should lead to a better characterization of (mainly oxygenated) BVOC emissions from these understudied ecosystems, allowing a better representation of those emissions in air quality and atmospheric chemistry and transport models. BVOC fluxes are obtained by the Disjunct Eddy Covariance by mass scanning (DEC-MS) technique, using a hs-PTR-MS instrument for BVOC analysis. Secondly, the eddy covariance BVOC flux measurements (especially at the grassland site) will be accompanied by ozone flux, chlorophyll fluorescence, photosynthesis and soil moisture measurements, amongst others, to allow linking alterations in BVOC emissions to stress episodes. Simultaneously, automated dynamic enclosures will be deployed in order to detect specific abiotic and biotic stress markers by PTR-MS and identify them unambiguously by GC-MS. Thirdly, the field measurements will be accompanied by laboratory BVOC flux measurements in an environmental chamber in order to better disentangle the responses of the BVOC emissions to driving factors that co-occur in field conditions and to determine the influence of single abiotic stressors on BVOC emissions. Next to a general presentation, some preliminary results of the project will be shown. [less ▲]

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See detailBiogenic Volatile Organic Compound (BVOC) emissions from agricultural crop species: is guttation a possible source for methanol emissions following light/dark transition?
Mozaffar, Ahsan ULg; Amelynck, Crist; Bachy, Aurélie ULg et al

in Geophysical Research Abstracts (2015, April), 17(EGU2015-2110-1),

In the framework of the CROSTVOC (CROp STress VOC) project, the exchange of biogenic volatile organic compounds (BVOCs) between two important agricultural crop species, maize and winter wheat, and the ... [more ▼]

In the framework of the CROSTVOC (CROp STress VOC) project, the exchange of biogenic volatile organic compounds (BVOCs) between two important agricultural crop species, maize and winter wheat, and the atmosphere has recently been measured during an entire growing season by using the eddy covariance technique. Because of the co-variation of BVOC emission drivers in field conditions, laboratory studies were initiated in an environmental chamber in order to disentangle the responses of the emissions to variations of the individual environmental parameters (such as PPFD and temperature) and to diverse abiotic stress factors. Young plants were enclosed in transparent all-Teflon dynamic enclosures (cuvettes) through which BVOC-free and RH-controlled air was sent. BVOC enriched air was subsequently sampled from the plant cuvettes and an empty cuvette (background) and analyzed for BVOCs in a high sensitivity Proton-Transfer Reaction Mass Spectrometer (hs-PTR-MS) and for CO2 in a LI-7000 non-dispersive IR gas analyzer. Emissions were monitored at constant temperature (25 °C) and at a stepwise varying PPFD pattern (0-650 µmol m-2 s-1). For maize plants, sudden light/dark transitions at the end of the photoperiod were accompanied by prompt and considerable increases in methanol (m/z 33) and water vapor (m/z 39) emissions. Moreover, guttation droplets appeared on the sides and the tips of the leaves within a few minutes after light/dark transition. Therefore the assumption has been raised that methanol is also coming out with guttation fluid from the leaves. Consequently, guttation fluid was collected from young maize and wheat plants, injected in an empty enclosure and sampled by PTR-MS. Methanol and a large number of other compounds were observed from guttation fluid. Recent studies have shown that guttation from agricultural crops frequently occurs in field conditions. Further research is required to find out the source strength of methanol emissions by this guttation phenomenon in real environmental conditions. [less ▲]

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See detailInterdire des OGM autorisés : on avance ou on recule ?
du Jardin, Patrick ULg

Article for general public (2015)

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See detailPlant biostimulants: Definition, concept, main categories and regulation
du Jardin, Patrick ULg

in Scientia Horticulturae (2015)

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See detailNext-generation sequencing as a tool for the molecular characterisation and risk assessment of genetically modified plants: Added value or not ?
Pauwels, Katia; De Keersmaecker, Sigrid; De Schrijver, Adinda et al

in Trends in Food Science & Technology (2015), 45

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See detailA consensual Diving-PAM protocol to monitor Posidonia oceanica photosynthesis
Gobert, Sylvie ULg; Lepoint, Gilles ULg; Silva, João et al

in PeerJ (2015)

The seagrass Posidonia oceanica is widely recognized as an effective bioindicator of the health status of Mediterranean coastal waters. Chlorophyll fluorescence measurements, in particular through the ... [more ▼]

The seagrass Posidonia oceanica is widely recognized as an effective bioindicator of the health status of Mediterranean coastal waters. Chlorophyll fluorescence measurements, in particular through the Pulse Amplitude Modulated (PAM) fluorometry method, are performed to study aquatic plant ecology and vitality and to assess their responses to diverse stressful factors. However, the current understanding of P. oceanica photosynthetic responses to environmental stresses does only allow scientists to use the PAM-method as a complementary tool to other more-robust monitoring techniques. Consequently, a more in-depth knowledge of the natural causes of variability of P. oceanica photosynthetic responses are a prerequisite to any surveys relying on that time and cost-effective method. In the framework of the STARECAPMED project, this work aimed to determine the influence of several environmental (depth, daytime, season) and plant-specific characteristics (leaf age, leaf part analyzed, epiphytic coverage) on the photosynthetic responses (Y, ETR, RLC) of P. oceanica. Water temperature, irradiance and several biochemical parameters of the seagrass (chl.a, chl.b, C, N, P, micronutrients such as Fe, Cu) were measured as well. The field survey was performed in a pristine meadow in the Calvi Bay, Corsica. Environmental and plant-physiological characteristics deeply influenced P. oceanica photosynthetic responses. As an example, ETR decreased with depth, contrary to Y that mostly increased. ETR was lower in the basal part of leaf blade, and the epiphytic coverage of leaf tips slightly increased their ETR compared to leaf tips cleaned of epiphytes. Depth and leaf part-related variations in RLC were also observed. Because of this natural variability, it appears essential to develop a consensual protocol of chlorophyll fluorescence measurements to publish reliable and comparable results between studies. We therefore notably suggest to perform measurements close to midday, when photosynthetic responses are the highest; at 10-15 m depth in order to avoid, among others, low depth light irradiance variability; on the middle part of the 3rd-4th external leaf, well developed, highly photosynthetic, and little epiphyted. Finally, because P. oceanica fluorescence was correlated with N, P and chl.b leaf contents, the PAM-method could afterwards be used as bioindicator technique, according to the protocol proposed. [less ▲]

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See detailBiotechnological uses of RNAi in plants: Risk assessment considerations
Casacuberta, J. M.; Devos, Y.; du Jardin, Patrick ULg et al

in Trends in Biotechnology (2015), 33(3), 145-147

RNAi offers opportunities to generate new traits in genetically modified (GM) plants. Instead of expressing novel proteins, RNAi-based GM plants reduce target gene expression. Silencing of off-target ... [more ▼]

RNAi offers opportunities to generate new traits in genetically modified (GM) plants. Instead of expressing novel proteins, RNAi-based GM plants reduce target gene expression. Silencing of off-target genes may trigger unintended effects, and identifying these genes would facilitate risk assessment. However, using bioinformatics alone is not reliable, due to the lack of genomic data and insufficient knowledge of mechanisms governing mRNA-small (s)RNA interactions. © 2014 Elsevier Ltd. [less ▲]

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See detailAllelopathic and autotoxicity effects of barley (Hordeum vulgare L. ssp. vulgare) root exudates
Bouhaouel, Imen; Gfeller, Aurélie; Fauconnier, Marie-Laure ULg et al

in BioControl (2014), Online First

The allelopathic activity of barley (Hordeum vulgare L. ssp. vulgare) root exudates was studied by comparing their effects on seedling establishment in barley itself and in two weed species, Bromus ... [more ▼]

The allelopathic activity of barley (Hordeum vulgare L. ssp. vulgare) root exudates was studied by comparing their effects on seedling establishment in barley itself and in two weed species, Bromus diandrus Roth. and Lolium rigidum Gaudin, using an original laboratory protocol, named ‘seed-after-seed’. In this protocol, the donor and the receiver species of watersoluble allelochemicals are grown one after the other in the same dishes, in conditions reducing resource competition between both species. Growth of all receptive species (weeds and barley) was inhibited in a dose-dependent manner, when using increasing barley seed densities (0, 8, 19 and 25 seeds per Petri dish). In our conditions, the barley varieties and landraces exhibited different allelopathic activities against weeds or barley. The allelopathic potential of the barley root exudates was also dependent on the receiver species. Indeed, the released allelochemicals proved to be more toxic against the weed plants than on barley itself. Furthermore, the toxicity of the allelochemicals increased after their release by roots, between day 0 and day 6. These allelochemicals might contribute to the plant community dynamics and their usefulness as bio-herbicides deserves further consideration. [less ▲]

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See detailBarley (Hordeum distichon L.) roots produce volatile aldehydes via the lipoxygenase/hydroperoxide lyase pathway with a strong age-dependent pattern
Delory, Benjamin ULg; Delaplace, Pierre ULg; du Jardin, Patrick ULg et al

Conference (2014, August 13)

In chemical ecology, the roles played by root-emitted volatile organic compounds (VOCs) in biotic interactions and the quantitative analysis of such chemicals in root tissues remain poorly documented. In ... [more ▼]

In chemical ecology, the roles played by root-emitted volatile organic compounds (VOCs) in biotic interactions and the quantitative analysis of such chemicals in root tissues remain poorly documented. In this context, this study aims at using a fully automated gas chromatography – mass spectrometry methodology allowing both identification and accurate quantification of VOCs produced by roots of a monocotyledonous plant species at five selected developmental stages from germination to the end of tillering. Results show that barley roots mainly produce four volatile aldehydes, namely hexanal, (E)-hex-2-enal, (E)-non-2-enal and (E,Z)-nona-2,6-dienal. These molecules are well-known linoleic and linolenic acid derivatives produced via the lipoxygenase/hydroperoxide lyase pathway of higher plants. Our findings contrast with analyses documented on aboveground barley tissues that mainly emit C6 aldehydes, alcohols and their corresponding esters. Multivariate statistical analyses performed on individual VOC concentrations indicate quantitative changes in the volatile profile produced by barley roots according to plant age. Barley roots produced higher total and individual VOC concentrations when young seminal roots emerged from the coleorhizae compared to older phenological stages. Moreover, results also show that the C6/C9 volatile aldehyde ratio was the lowest at the end of tillering while the maximum mean value of this ratio was reached in seven day-old barley roots. [less ▲]

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See detailAllo- and autoinhibition in barley and great brome: a laboratory study
Bouhaouel, Imen ULg; Gfeller, Aurélie; Fauconnier, Marie-Laure ULg et al

Conference (2014, February 08)

Detailed reference viewed: 65 (24 ULg)