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See detailGenotype contribution to the chemical composition of banana rachis and implications for thermo/biochemical conversion
Tiappi Deumaga, Mathias Florian; Happi Emaga, Thomas; Tchokouassom, Raphael et al

in Biomass Conversion and Biorefinery (in press)

Chemical composition of banana rachis from three varieties (Grande naine, Pelipita, and CRBP969) was ana- lyzed, and the genotype contribution to composition variabil- ity was investigated. Wet chemistry ... [more ▼]

Chemical composition of banana rachis from three varieties (Grande naine, Pelipita, and CRBP969) was ana- lyzed, and the genotype contribution to composition variabil- ity was investigated. Wet chemistry and instrumental analysis procedures (X-ray diffraction, 31P NMR spectroscopy, and thermogravimetry) were used. Some significant differences were found among the three genotypes: GN-AAA genotype was found to be significantly the highest in ash fraction (30.16 %) and the lowest in acid insoluble lignin (6.58 %) at 95 % confidence level. It showed also the highest content in potassium (43.5 % in ash). Implication of compositional dif- ferences on valorization efficiency by biochemical or thermo- chemical pathways was investigated. For this purpose, corre- lation coefficients between compositional characteristics and yields in volatile compounds from pyrolysis and glucose yields from enzymatic saccharification were analyzed. Ash content was revealed to be the main drawback parameter for volatile yields from pyrolysis (r = −0.93), while for glucose yields during saccharification were limited mainly by the con- tent in guaiacyl units of the lignin fraction (r = −0.98). How- ever, a strong and positive correlation was established be- tween the volatiles yield and the acid insoluble lignin content (r = 0.98) Thus, according to these observations and based on their compositional significant differences, GN-AAA was the better candidate for bioconversion pathway while PPT-ABB and CRBP969-AAAB samples were shown to be better can- didates for thermochemical conversion pathway. This work gives important preliminary information for considering ba- nana rachis as an interesting feedstock candidate for biorefinery. [less ▲]

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See detailScreening for interesting elicitors to protect wheat against Zymoseptoria tritici
Le Mire, Géraldine ULg; Siah, Ali; Fauconnier, Marie-Laure ULg et al

Conference (2015, May 19)

Plants face an array of biotic and abiotic stresses in their environment, making it necessary to use various chemical inputs to maintain satisfactory yield. Today, conventional agriculture is evolving ... [more ▼]

Plants face an array of biotic and abiotic stresses in their environment, making it necessary to use various chemical inputs to maintain satisfactory yield. Today, conventional agriculture is evolving towards more sustainable practices, out of respect for human health and the environment. Elicitors are considered as promising biological control tools and draw major interest in IPM strategies. These plant-immunity triggering compounds, also called “stimulators of plant natural defenses”, induce a general and systemic resistance in the plant to various diseases. Although numerous elicitors have already been identified and some of them reached the market since the late 1970s, further investigations are still required to better understand the mode of action of these molecules in the plant and ensure a consistent efficiency under various field conditions. Few elicitors have yet been successfully tested and formulated to protect crop plants such as wheat, which is cultivated over large areas in Europe. This study focuses on the screening of ten potential elicitor products of various origins and structures to protect winter wheat against the fungal pathogen Zymoseptoria tritici. Greenhouse trials were carried out to measure the ability of the different products to reduce disease foliar symptoms (necrosis, chlorosis and pycnidia). In addition, the phytotoxicity and biocide activities of these products were evaluated under greenhouse and laboratory conditions, respectively. The corresponding results will be presented and discussed with the perspective to choose the best elicitor candidates and to undertake investigations on the signaling pathway and the influence of environmental parameters on the elicitation capacity. [less ▲]

Detailed reference viewed: 33 (13 ULg)
See detailSurfactin: a receptor-independent bacterial elicitor of plant immunity?
Luzuriaga Loaiza, Walter ULg; Legras, Aurelien; Crowet, Jean-Marc ULg et al

Scientific conference (2015, May 13)

Detailed reference viewed: 21 (3 ULg)
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See detailInteractions of natural rhamnolpids produced by Pseudomonas aeruginosa with plant model membranes
Polo Lozano, Damien ULg; Nasir, Mehmet Nail ULg; Deleu, Magali ULg et al

Poster (2015, January 30)

It is well known that chemical pesticides have harmful effects on human health and environment. In this context, the interest for alternative products such as biopesticides is increasing. Among them ... [more ▼]

It is well known that chemical pesticides have harmful effects on human health and environment. In this context, the interest for alternative products such as biopesticides is increasing. Among them, elicitors act on the plants by inducing systemic resistance against diseases caused by fungal, viral, bacterial agents and insects. Rhamnolipids are surface active molecules produced mainly by various strains of the bacterium Pseudomonas aeruginosa. These secondary metabolites are composed of one to three fatty acids with various chain lengths linked through a glycosidic bond to one or two rhamnose moieties. The fatty acids are linked together through an ester bond. These molecules have shown several biological activities including plant defense stimulation. It has been suggested that this elicitor activity could be related to an interaction of rhamnolipids with the lipid bilayer of the plant plasma membrane (PPM) and lead to its destabilization, which can activate the plant defense signaling pathways. In this context, interactions of two rhamnolipids (Rha-C10-C10 and Rha-Rha-C10-C10) with biomimetic membranes of PPM such as Langmuir monolayers and multilayers were investigated using biophysical and in silico approaches. [less ▲]

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See detailBiochemical methane potential of residues of three banana varieties from Cameroon : fresh and dry peduncles
Awedem wobiwo, Florent; Happi Emaga, Thomas; Fokou, Elie et al

Poster (2015, January 30)

In Cameroon , the ratio of energy cost to standard of living for both electric and fuel energy is higher than in USA and EU. The local energy needs could be met by valorizing local wastes in an ... [more ▼]

In Cameroon , the ratio of energy cost to standard of living for both electric and fuel energy is higher than in USA and EU. The local energy needs could be met by valorizing local wastes in an environmentally and economically sustainable way. Banana and plantain plants produce significant quantities of post-harvest biomass wastes such as bulbs, pseudo stems, leaf sheaths, petioles–midribs, leaf blades, peduncles, rachis and blossoms which can be converted to methane-rich biogas by anaerobic digestion (AD). AD is a natural process of degradation of organic materials. [less ▲]

Detailed reference viewed: 38 (4 ULg)
See detailPGPR elicitors of plant immunity: insights into the molecular basis of surfactin perception
Luzuriaga Loaiza, Walter ULg; Legras, Aurélien; Franzil, Laurent ULg et al

Scientific conference (2015)

Detailed reference viewed: 34 (1 ULg)
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See detailA Stereocontrolled Synthesis of the Hydrophobic Moiety of Rhamnolipids
Menhour, Boudjema; Mayon, Patrick; Plé, Karen et al

in Tetrahedron Letters (2015), 56

Detailed reference viewed: 32 (3 ULg)
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See detailAnalysis of the interactions of natural elicitor rhamnolipids with plant plasma membranes by in silico methods
Polo Lozano, Damien ULg; Nasir, Mehmet Nail ULg; Deleu, Magali ULg et al

Poster (2014, October 20)

Rhamnolipids are surface active molecules produced mainly by various strains of the bacterium Pseudomonas aeruginosa. These secondary metabolites are composed of one to three fatty acids with various ... [more ▼]

Rhamnolipids are surface active molecules produced mainly by various strains of the bacterium Pseudomonas aeruginosa. These secondary metabolites are composed of one to three fatty acids with various chain lengths linked through a glycosidic bond to one or two rhamnose moieties. The fatty acids are linked together through an ester bond. These molecules have shown several biological activities including plant defense stimulation. It has be suggested that this elicitor activity could be related to an interaction of rhamnolipids with the lipid bilayer of the plant plasma membrane (PPM) and lead to its destabilization, which can activate the plant defense signaling pathways. In this context, interactions of two rhamnolipids (Rha-C10-C10 and Rha-Rha-C10-C10) with membrane models and lipidic constituents of the PPM were investigated using in silico approaches. Most probable chemical structures of the rhamnolipids were determined using the STRUCTURE TREE procedure according to the molecule potential energy. The ability of these rhamnolipid structures to insert within the PPM was assessed using IMPALA simulations. IMPALA uses a membrane model in which phospholipids molecules are implicitly modeled by an empirical function and the membrane properties are modeled by energetic restraints. The ability of each rhamnolipid structure to form an assembly with several PPM constituents (phospholipid (PLPC), sterols (Sitosterol, Stigmasterol, Campesterol) and sphingolipids (GIPC, Glucosylceramide)) was calculated using the HYPERMATRIX procedure, which calculate and minimize the energies of interaction between all molecules of the complex until the lowest energy structure is reached. [less ▲]

Detailed reference viewed: 57 (5 ULg)
See detailScreening of elicitor candidates on winter wheat against Septoria tritici
Le Mire, Géraldine ULg; Deleu, Magali ULg; Ongena, Marc ULg et al

Scientific conference (2014, October 14)

The various experiments to be held prior to elicitor screening are detailed, along with the screening metholodogy. Explanation is given on the increasing interests of plant elicitors, or "stimulators of ... [more ▼]

The various experiments to be held prior to elicitor screening are detailed, along with the screening metholodogy. Explanation is given on the increasing interests of plant elicitors, or "stimulators of natural defenses", for the sustainability of our agro-ecosystems. [less ▲]

Detailed reference viewed: 43 (12 ULg)
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See detailElicitor screening to protect winter wheat against Septoria tritici Blotch: preliminary results
Le Mire, Géraldine ULg; Deleu, Magali ULg; Ongena, Marc ULg et al

Conference (2014, September)

Elicitors are plant immunity-triggering compounds which are currently considered as one of the most promising tools in agriculture for the induction of plant resistance to various diseases (Mejía-Teniente ... [more ▼]

Elicitors are plant immunity-triggering compounds which are currently considered as one of the most promising tools in agriculture for the induction of plant resistance to various diseases (Mejía-Teniente et al., 2010). By contributing to both economic and environmental performances of agroecosystems, they can help reducing the use of chemical inputs. Although some elicitor products are already available on the market, it appears that a variable efficiency in the field, along with an uneasy integration in the current legislation and agricultural strategies, make these tools difficult to use (Walters, Ratsep, & Havis, 2013). Besides these limitations, few elicitor treatments have yet been efficiently and specifically designed to protect crop plants such as wheat, which is grown and consumed worldwide, against major diseases threatening both their yield and quality. There is a strong need to better understand the mechanisms of induced resistance in plants and develop elicitor use in agriculture. A phD research is currently led in Gembloux Agro Bio-Tech to develop a method based on eliciting agents, tested in greenhouse and field conditions, to protect winter wheat against major diseases, namely Septoria tritici, Fusarium graminearum and Fusarium culmorum. This project focuses on the screening of a large number of elicitors from different origins and structures. In 2014, we focused the first screening experiments on the protection of wheat against Septoria tritici Blotch (STB). Two winter wheat genotypes were tested: susceptible ‘Avatar’ and semi-resistant ‘Sy Epson’. Plants at 3-leaf stage were first sprayed till runoff with different concentrations of elicitors, and then inoculated 5 days later with a Septoria tritici spore suspension (106 spores mL-1) using a hand sprayer. Control plants were treated, prior to disease inoculation, with sterile water (negative control) or with BION® (ASM, Syngenta Europe; positive control). The disease severity and incidence were scored every 2 days for 28 days post-inoculation (d.p.i) by measuring the percentage of area covered with lesions and bearing pycnidia on the third leaf. The first results of these tests should enable a first discrimination of elicitors considering their dose-efficiency to reduce disease severity. After further screening of all the elicitors in hand, a determination of the elicitation pathways of the most efficient molecules tested will be undertaken. We intend to study the influence of various factors (i.e Temperature, relative humidity, plant development stage) on the elicitation potential and develop a formulation to be finally tested under field conditions. [less ▲]

Detailed reference viewed: 66 (11 ULg)