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See detailImpact of Myzus persicae infestation on the volatile emission of Arabidopsis thaliana Col-0.
Hien, Truong Thi Dieu ULg; Delaplace, Pierre ULg; Francis, Frédéric ULg et al

Poster (2012, July 22)

Being members of complex communities, plants often emit a wide range of volatile organic compounds to defend themselves against insect invasions. Although many studies exist on insect-induced plant ... [more ▼]

Being members of complex communities, plants often emit a wide range of volatile organic compounds to defend themselves against insect invasions. Although many studies exist on insect-induced plant volatile emission, most of them either compare the influences of various herbivore species on one plant species or the impact of a given herbivore on several host plant species. Moreover, informations related to the influence of insect density as well as the infestation duration are still needed. Here, we showed that a sucking insect – Myzus persicae (green peach aphid) induced the volatile emission from Arabidopsis thaliana Columbia wild-type (A.thaliana Col-0) under laboratory conditions based on results obtained by solid-phase micro-extraction coupled with gas chromatography - mass spectrometry (SPME-GC/MS). The released volatile blend was discussed in relation to related biosynthesis pathways and functions. These included terpenoids, green leaf volatiles, alcohols and isothiocyanate. The qualitative and overall proportion of volatile components differed depended on the number and residence duration of aphids on leaves. By studying the effects of sucking insect stresses to plant, we not only aim to contribute to the fundamental understanding of the emission of volatile components in the interaction between plants and pests, but also to provide standardised and easy to use assays to assess A.thaliana volatile changes according to cross stresses, including both biotic and abiotic ones in ongoing experiments. [less ▲]

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See detailRhizobacterial volatile organic compounds modulate biomass production and root architecture in Arabidopsis thaliana (L.) Heynh.
Varin, Sébastien; Saunier de Cazenave-Mendaluk, Magdalena ULg; Ormeno-Lafuente, Elena et al

Poster (2012, February 10)

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See detailDescribing and modelling root and shoot growth and development in Brachypodium distachyon (L.) Beauv
Delory, Benjamin ULg; Delaplace, Pierre ULg; Gfeller, Aurélie ULg et al

Poster (2011, October 19)

Due to its small size, its short developmental cycle and its close phylogenetic relationship with the Triticeae tribe, Brachypodium distachyon (L.) Beauv. has been proposed as a model species for ... [more ▼]

Due to its small size, its short developmental cycle and its close phylogenetic relationship with the Triticeae tribe, Brachypodium distachyon (L.) Beauv. has been proposed as a model species for temperate cereals. In this context, this work aims to describe and model root and shoot growth and development of B. distachyon (Bd21-1) grown under controlled environmental conditions [22°C, 65% RH, 20h light, 95 µmol.m-2.s-1 (PAR, LED lighting)]. For this purpose, vernalized caryopses were sown in a substrate consisting of vermiculite and compost (80/20, v/v). Growth and development of the above and belowground parts were monitored for 70 days. Dry and fresh masses of plant organs were measured every seven days from sowing. Biomasses of adventitious and seminal roots were measured separately. The number of spikelets on the main stem and on tillers was also counted on plants aged of 70 days. The modelling of root and shoot growth was achieved by calibrating sigmoidal growth models to the mean biomass values measured at each day of analysis. For each plant organ, the growth model selected was the one with the lowest residual variance. Finally, developmental stages identified for B. distachyon were compared with those defined for cereal crops by Zadoks et al. (1974). Maximum rates of fresh and dry shoot biomass production were 29,5 and 14,2 mg.day-1 respectively. Based on modelling, these values seem to be reached 49 and 72 days after sowing. Results also show that the fresh mass of adventitious roots at day 42 is significantly higher than that of seminal roots. Maximum rates of fresh and dry root biomass production were 6,9 and 0,8 mg.day-1 respectively, and were reached after 37 and 43 days. [less ▲]

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See detailLes volatils racinaires de l’orge : un langage souterrain ?
Barsics, Fanny ULg; Gfeller, Aurélie ULg; Fauconnier, Marie-Laure ULg et al

Scientific conference (2011, October 13)

Cette présentation résume les avancées du projet Rhizovol après une année de travaux de recherche.

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See detailBiocontrol proteomics:Implication of the pentoses phosphates pathway in the antagonist effect of Pichia anomala against Botrytis cinerea on apple.
Kwasiborski, Anthony ULg; renaut, Jenny; Delaplace, Pierre ULg et al

Conference (2011, August 31)

Pichia anomala strain K was previously identified as an efficient biocontrol agent of the apple pathogen, Botrytis cinerea. Further study demonstrated the complexicity of the mode of action of P. anomala ... [more ▼]

Pichia anomala strain K was previously identified as an efficient biocontrol agent of the apple pathogen, Botrytis cinerea. Further study demonstrated the complexicity of the mode of action of P. anomala against B. cinerea. A molecular study revealed implication of exo-β-1,3-glucanases in the mode of action of P. anomala but suggested implication of other factors. The present study aims to increase our knowledge of the mode of action of P. anomala strain Kh6 against B. cinerea using an in situ approach allowing interactions between organisms, and the proteomic tool allowing to study the ultime expression of the genome. One wound per apple were covered by a membrane and inoculated by P. anomala then by B. cinerea or not. Samples were collected at different incubation times to identify the responses of P. anomala to the presence of B. cinerea. After extraction, proteins were separated on 2-D gels. Spots influenced were identified by MALDI-ToF. In exponential phase, P. anomala Kh6 orientates its energetic metabolism from the glycolysis to the oxidative phosphorylation and sets up the pentose phosphate pathway. Thanks to this new pathway, P. anomala probably obtains energy and nucleic acids allowing to colonize the wound as fast as in absence of B. cinerea. In stationary phase, no differences in the P. anomala energetic metabolism, in absence and in presence of B. cinerea were observed. During that phase, P. anomala seems to use the alcoholic fermentation in order to face the nutrients impoverishment of the substrate. [less ▲]

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See detailVolatile organic compounds of the roots of barley and their role in the rhizosphere
Fiers, Marie ULg; Barsics, Fanny ULg; Camerman, Marc ULg et al

Poster (2011, May 24)

Volatile organic compounds emitted by plants are known to intervene with various biotic environmental factors. Up to now, most of the studies have been focused on aerial volatiles and root liquid exudates ... [more ▼]

Volatile organic compounds emitted by plants are known to intervene with various biotic environmental factors. Up to now, most of the studies have been focused on aerial volatiles and root liquid exudates. Very few researches have been completed concerning belowground volatiles released into the rhizosphere despite their potential capacity to carry information between organisms. The Rhizovol project, started in autumn 2010, involves 5 different units of Gembloux Agro-Bio Tech collectively studying the production of belowground volatiles by barley roots underlying various biotic interactions in the rhizosphere. Some preliminary results of each partner of the project will be presented. To achieve this goal, analytical methods allowing the sampling, separation, identification and quantification of belowground volatile compounds have to be developed, taking into account their potential modifications in the rhizosphere once released by the roots. They enable the subsequent characterization and study of the interactions between barley and its rhizospheric partners chosen for this study. These interactions imply three types of organisms: beneficial organisms, pathogenic agents and plant and insect pests. Beneficial organisms can promote the growth of barley by the emission of volatiles; on the other hand barley can support their growth and metabolism. These phenomenons will be assessed by the study of 19 strains of plant growth-promoting bacteria (PGPR). Three pathogenic agents - two fungi (Fusarium culmorum and Cochliobolus sativus) and one virus (Barley yellow dwarf virus) - were chosen as they are known to cause various diseases on barley, especially on roots. The attractive or repellent effects of barley root volatiles on the pathogenic agents or their vectors, as well as the effect of volatiles on the diseases evolution will be evaluated. The project also includes several types of pests such as plants and insects. Plants can compete with barley for space and nutrients through volatile interactions. This will be assessed by the study of autotoxicity by barley itself and allelopathy with 8 weeds and a hemiparasitic plant (Rhinanthus minor). The effects of barley volatiles can also impact the severity of the attacks by insects. This part will be conducted with wireworms as they represent worldwide known pests, and aphids, through their viral vector role. Eventually, as soil characteristics can strongly influence the diffusion of volatile compounds, the diffusion behaviour of the identified volatile biomolecules through the soil will be modelled. Tritrophic interactions (e.g. insect-plant-pathogenic fungi) will be studied based on each bitrophic interaction results. Over-all, the Rhizovol project aims at improving the knowledge of interactions mediated by volatile compounds in the rhizosphere and at establishing new biocontrol methods that could contribute to integrated disease and pest management systems. [less ▲]

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See detailIn situ proteome study of Pichia anomala strain K, an antagonist of the apple pathogen Botrytis cinerea
Kwasiborski, Anthony ULg; Renaut, Jenny; Delaplace, Pierre ULg et al

Conference (2011, May 24)

Postharvest fungal pathogens, mainly Botrytis cinerea, Penicillum expansum and Gloeosporium spp., annually cause 5-20% losses of fruit. Control measures against these diseases include chemical fungicide ... [more ▼]

Postharvest fungal pathogens, mainly Botrytis cinerea, Penicillum expansum and Gloeosporium spp., annually cause 5-20% losses of fruit. Control measures against these diseases include chemical fungicide applications, but the development of resistant fungal explains the growing interest for biological control. Pichia anomala strain K was previously identified as an efficient antagonist of pathogens on apples. Indeed, the percentage of protection of P.anomala against B.cinerea reached from 90 to 100% on apple wounds according to the experimental conditions. Microbiological, biochemical and molecular approaches demonstrated the implication of exo-β-1,3-glucanases in the mechanism of action of P.anomala. However, study of these mechanisms could be improved by observations under natural infection conditions in order to take into account the tripartite interactions host/antagonist/pathogen. The proteomic tool allowed an overview of process implicated in the antagonism against B.cinerea in such conditions. One 50mm wound per apple were covered by a membrane and inoculated by a P.anomala suspension then by B.cinerea or not. Samples were collected during the exponential and stationary phase to identify the early and later responses to the presence of B.cinerea. After extraction, proteins were separated on 2DE gels. Spots influenced by the presence of B.cinerea in exponential and stationary phases were identified by MALDI-ToF. One hundred five and sixty spots of proteins were influenced by the presence of B.cinerea in exponential and stationary phase respectively. In exponential phase, influenced proteins were implicated in the different steps of the proteins biosynthesis: amino acid synthesis, translation or mRNA maturation and in energy synthesis. On the other hand, in stationary phase, influenced proteins were mainly implicated in energy metabolic pathway: glycolysis, alcoholic fermentation or gluconeogenesis. The presence of B.cinerea seemed to induce a slowdown in the metabolism of P.anomala without influenced its growth. Further studies have to be realized to understand the complexity of these modes of action. [less ▲]

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See detailAntioxidants involvement in the Ageing of Non-Green Organs
Delaplace, Pierre ULg; Fauconnier, Marie-Laure ULg; du Jardin, Patrick ULg

in Gupta, S. Dutta (Ed.) Reactive oxygen species and antioxidants in higher plants (2010)

Detailed reference viewed: 39 (18 ULg)