References of "Jijakli, Haissam"
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See detailFirst Characterization of the Volatile Organic Compounds Emitted by Banana Plants (Musa sp.)
Berhal, Chadi ULg; De Clerck, Caroline ULg; LEVICEK, Carolina et al

Conference (2017, June 16)

Banana fruit (Musa sp.) ranks fourth in developing world's production, and has economical and nutritional key values. The popular and most dominant variety of the dessert banana group is the Cavendish ... [more ▼]

Banana fruit (Musa sp.) ranks fourth in developing world's production, and has economical and nutritional key values. The popular and most dominant variety of the dessert banana group is the Cavendish variety, and Plantain represents that status for the cooking banana group. Despite the importance of the Volatile Organic Compounds (VOCs), which are secondary metabolites with a high vapour pressure, in their utility in the plant protection and communication processes, they were never documented for the plant itself. Thus, the aim of this PHD thesis is to study the VOCs emitted by the plant, rather than their fruits or flowers. A protocol was optimized for the extraction of the banana plant's VOCs. The results of the first analysis showed 11 VOCs for the Cavendish, mainly (E,E)-α-farnesene (87.90 ± 11.28 ng/µl), methyl salicylate (33.82 ± 14.29) and 6-methyl-5-hepten-2-one (29.60 ± 11.66), and 14 VOCs for the Pacific Plantain cultivars, mainly (Z,E)-α-farnesene (799.64 ± 503.15),(E,E)-α-farnesene (571.24 ± 381.70) and (E) β ocimene (241.76 ± 158.49). Most of these compounds belong to the terpenes group (8 for Cavendish, 10 for Pacific Plantain). The other compounds detected were ketones, esters and aldehydes. Eight compounds were common between the two varieties (myrcene, Z and E β-ocimene, 6-methyl-5-hepten-2 one, 6-methyl-3,5-hepadien-2-one, a-farnesene, methyl salicylate and β-ionone). This exploratory study paves the way for an in-depth characterisation of VOCs emitted by Musa plants. [less ▲]

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See detailStudy of volatile organic compounds active against barley pathogens
De Clerck, Caroline ULg; Kaddes, Amine ULg; Fiers, Marie et al

Conference (2017, May 23)

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See detailStudy of VOCs in the interaction between Banana and Foc TR4
Berhal, Chadi ULg; De Clerck, Caroline ULg; LEVICEK, Carolina et al

Poster (2017, May 23)

Banana fruit (Musa sp.) ranks fourth in term of worldwide production, and has economical and nutritional key values. The popular and most dominant variety of the dessert banana group is the Cavendish ... [more ▼]

Banana fruit (Musa sp.) ranks fourth in term of worldwide production, and has economical and nutritional key values. The popular and most dominant variety of the dessert banana group is the Cavendish variety. Nowadays, the Cavendish is endangered by the newly emergent race of the Panama disease, caused by the fungal pathogen Fusarium oxysporum f.sp. cubense TR4 (Foc TR4). Despite the importance of the Volatile Organic Compounds (VOCs), which are secondary metabolites with a high vapour pressure, in their utility in the plant protection processes, they were never documented as a way to manage this disease on Cavendish. Thus, the aim of this PhD thesis is to study the VOCs in the specific interaction Cavendish/Foc TR4, as a way to manage this threat. Based on the work previously done with other plants at Gembloux Agro-Bio Tech/University of Liège/Belgium, a protocol was optimized for the extraction of the banana plant’s VOCs. And in parallel, models of in-vitro and in-vivo inoculations are under development, in order to distinguish the root zone from the upper part of the plant in the study. The results of the first analysis showed that the majority of the Cavendish VOCs belongs to the terpenes group, as well as ketones and an organic ester. The identified key VOCs of the interaction will be subject to toxicity tests, in order to determine their effect on the development of the plant and the pathogen. The banana plant is a staple food for more than 400 Million people in the world, while this disease persists as a major threat for its production, and this original study could contribute to the fight against this threatening disease. [less ▲]

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See detailEssential oil of Tunisian plant: biopesticide applied in agricultural system
Ben Kaab, Sofiène ULg; ksouri, riadh; Jijakli, Haissam ULg

Conference (2017, May 23)

The use of plant-derived products in postharvest disease management may be a valid alternative to conventional chemical treatments (Pane et al., 2016). Unfavorable environmental conditions (such as salt ... [more ▼]

The use of plant-derived products in postharvest disease management may be a valid alternative to conventional chemical treatments (Pane et al., 2016). Unfavorable environmental conditions (such as salt and drought) increase production and accumulation of reactive oxygen species (ROS). Consequently, Tunisian plants have developed adaptive responses including the synthesis of specific bioactive molecules used for medical and nutritional purposes (Ksouri et al., 2012). In that context, the main objective of the present study was the identification of essential oils from Tunisian plants against the important plant pathogens, particularly in Europe. The study began with the selection of endemic medicinal plant suspected to present antimicrobial properties. The essential oil was extracted by hydrodistillation using a Clevenger type apparatus (with a yield of 1.2%). The chemical composition of the essential oil obtained by hydro-distillation from the aerial parts was analyzed by GC/MS. Therefore, antifungal activity was evaluated against Fusarium culmorum, Fusarium oxysporum and Penicillium italicum, using ELISA microplates with a blocked randomized design, as described previously (Kouassi et al., 2012). In addition, the essential oil was then tested for their herbicidal activities in pre-emergence and post-emergence assays against three weeds species. The chromatographic analysis showed a complex mixture where twenty compounds were identified accounting for 98.75 % of the total oil. Monoterpenes was represented by 71.73 %. The dominant monoterpenes are α Pinene (7.09%), 1,8-Cineole (54.6%) and Camphor (12.27%). Essential oil reduced significantly spores germination in a dose-dependent manner. Their fungistatic activity reached 100% at 0.6% against Fusarium oxysporum . In the dose response bioassay, the essential oil reduced seed germination rate of Phalaris minor, Sylibum marianum and Trifolium incanatum. Seedling growth was measured by shoot and root lengths at day 7. At 0.5%, essential oil reduced 100% seed germination. Post-emergence bioassays consisted in spraying essential oil at 3 concentrations (0.75, 2 and 3.4 %) at 2 leaves stage of three weeds species. Pelargonic acid was used as commercial positive control at 3.4%. At 0.75% and 2%, the essential oil do not show any sign of injury. However, only at 3.4 %, the spraying of essential oil showed visible injury ranging from wilting (after 1 day) and chlorosis (after 3 day) on Trifolium incanatum and Phalaris minor. After formulation, to enhance the distribution, the coverage and the penetration of the active molecules, the essential oil presented a high herbicidal activity. In conclusion, this work allowed to open new perspectives on the application of Tunisian essential oil as Novel biocontrol strategies against damageable plant pathogens and weeds. [less ▲]

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See detailFirst Characterisation of Volatile Organic Compounds Emitted by Banana Plants
Berhal, Chadi ULg; De Clerck, Caroline ULg; Fauconnier, Marie-Laure ULg et al

in Scientific Reports (2017)

Banana (Musa sp.) ranks fourth in term of worldwide fruit production, and has economical and nutritional key values. The Cavendish cultivars correspond to more than 90% of the production of dessert banana ... [more ▼]

Banana (Musa sp.) ranks fourth in term of worldwide fruit production, and has economical and nutritional key values. The Cavendish cultivars correspond to more than 90% of the production of dessert banana while cooking cultivars are widely consumed locally around the banana belt production area. Many plants, if not all, produce Volatile Organic Compounds (VOCs) as a means of communication with their environment. Although flower and fruit VOCs have been studied for banana, the VOCs produced by the plant have never been identified despite their importance in plant health and development. A volatile collection methodology was optimized to improve the sensitivity and reproducibility of VOCs analysis from banana plants. We have identified 11 VOCs for the Cavendish, mainly (E,E)-α-farnesene (87.90 ± 11.28 ng/μl), methyl salicylate (33.82 ± 14.29) and 6-methyl-5-hepten-2-one (29.60 ± 11.66), and 14 VOCs for the Pacific Plantain cultivar, mainly (Z,E)-α-farnesene (799.64 ± 503.15), (E,E)-α-farnesene (571.24 ± 381.70) and (E) β ocimene (241.76 ± 158.49). This exploratory study paves the way for an in-depth characterisation of VOCs emitted by Musa plants. [less ▲]

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See detailStrategic Points in Aquaponics
Junge, Ranka; König, Bettina; Villarroel, Morris et al

in Water (2017), 9(182),

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See detailLessons learned from the virus indexing of Musa germplasm: insights from a multiyear collaboration
De Clerck, Caroline ULg; Crew, Kathy; Van den Houwe, Ines et al

in Annals of Applied Biology (2017)

The Bioversity International Transit Center (ITC) for banana hosts more than 1500 accessions largely covering the genetic diversity of the genus Musa. Its objective is to conserve this genetic diversity ... [more ▼]

The Bioversity International Transit Center (ITC) for banana hosts more than 1500 accessions largely covering the genetic diversity of the genus Musa. Its objective is to conserve this genetic diversity and to supply plant materials to users worldwide. All the Musa accessions must be tested for virus presence and, if infected, virus elimination must be attempted, to enable the supply of virus-free plant material. An international collaborative effort launched under the auspices of Bioversity International (2007–2013) finally led to the implementation of a two-step process to test the accessions. The first step, called pre-indexing, involved only molecular tests and was designed as a pre-screen of new germplasm lines or existing accessions to reduce the need for post-entry virus therapy and repeated virus indexing. The second step, called full indexing, was performed on either older existing accessions or newer accessions which tested negative during pre-indexing, and involvedmolecular tests, transmission electron microscopy (TEM) and symptom observation. In total, 270 germplasm lines (434 samples) were pre-indexed; while full indexing was carried out on 243 accessions (68 of which had been pre-indexed). A significant proportion of the samples tested during pre-indexing was infected with at least one virus (68%), showing the utility of this early pre-screening step. Banana streak OL virus and Banana mild mosaic virus were the most commonly detected viruses during both pre- and full indexing. For 22 accessions, viral particles were observed by TEM in full indexing while the molecular tests were negative, underlining the importance of combining various detection techniques. After full indexing, viruses were not detected in 166 accessions, which were then released for international distribution from the ITC. This publication exemplifies how the practical application of diagnostic protocols can raise fundamental questions related to their appropriate use in routine practice and the need for their continuous monitoring and improvement after their first publication. [less ▲]

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See detailTHE LACTOPEROXIDASE SYSTEM, A NATURAL BIOCHEMICAL BIOCONTROL AGENT FOR PRE- AND POST-HARVEST APPLICATIONS
Bafort, Françoise ULg; Parisi, Olivier ULg; Perraudin, Jean-Paul et al

in Journal of Phytopathology (2017), 165(1), 22-34

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See detailPrevalence of viruses infecting plantain (Musa sp., AAB genome) in the major growing regions in Cote d'Ivoire
Kouadio, Kouakou Théodore; De Clerck, Caroline; Agneroh, Thérèse Atcham et al

in African Journal of Agricultural Research (2016), 11(44), 4532-4541

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See detailLettuce (Lactuca sativa L. var. Sucrine) Growth Performance in Complemented Aquaponic Solution Outperforms Hydroponics
Delaide, Boris; Goddek, Simon; Gott, James et al

in Water (2016), 8(467),

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See detailStudy of the volatile organic compounds in the interaction between banana plants and the fungal disease Fusarium oxysporum f.sp. cubense Tropical Race 4 (FocTR4)
Berhal, Chadi ULg; De Clerck, Caroline ULg; LEVICEK, CAROLINA et al

Conference (2016, October 11)

Banana fruit (Musa sp.) ranks fourth in term of worldwide production, and has economical and nutritional key values. Cavendish is the popular and most dominant variety of the dessert banana group ... [more ▼]

Banana fruit (Musa sp.) ranks fourth in term of worldwide production, and has economical and nutritional key values. Cavendish is the popular and most dominant variety of the dessert banana group. Nowadays, it is endangered by the emergent race of the Panama disease, caused by Fusarium oxysporum f.sp. cubense TR4 (Foc TR4). Despite the importance of the Volatile Organic Compounds (VOCs), which are secondary metabolites with a high vapour pressure, and their role in plant protection, they have never been documented as a way to manage this disease on Cavendish. Thus, the aim of this PhD thesis is to study the VOCs in the specific interaction Cavendish/Foc TR4, as a way to manage this threat. Based on the work previously done with other plants at Gembloux Agro-Bio Tech, a protocol was optimized for the extraction of the banana plant’s VOCs. In parallel, models of in-vitro and in-vivo inoculations are under development to distinguish the VOCs emitted by the root zone and those emitted by the aerial part of the plant. The results of the first analysis showed that the majority of the Cavendish VOCs belongs to the terpenes group, as well as ketones and an organic ester. The VOCs specifically emitted during the plant-pathogen interaction will be studied more in depth by evaluating their effect on the plant and the pathogen. At long term, and depending on the results, agro-ecological applications of this knowledge could include breeding for new variety or combining banana with other plants expressing VOCs against Foc TR4, applying VOCs on field to stimulate plant defences or to contain the pathogen. [less ▲]

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See detailExtremophile plants as source of biopesticides against European damageable plant pathogens
Ben Kaab, Sofiène ULg; Parisi, Olivier ULg; De Clerck, Caroline ULg et al

Poster (2016, September 14)

The use of plant-derived products in postharvest disease management may be a valid alternative to conventional chemical treatments (Pane et al., 2016). Unfavorable environmental conditions (such as salt ... [more ▼]

The use of plant-derived products in postharvest disease management may be a valid alternative to conventional chemical treatments (Pane et al., 2016). Unfavorable environmental conditions (such as salt and drought) increase production and accumulation of reactive oxygen species (ROS). Consequently, extremophile plants have developed adaptive responses including the synthesis of specific bioactive molecules used for medical and nutritional purposes (Ksouri et al., 2012). In that context, the main objective of the present study was the identification of effective plant extracts and essential oils from extremophile plants against the most important plant pathogens in Europe (in term of loss, treatment necessity and/or cost). The study began with the selection of four endemic medicinal species suspected to be antimicrobial due to their wealth of phenolic and terpene compounds, such as flavonoids, phenolic acids, and coumarins (Ksouri et al., 2012). Each of the aerial plant materials was grounded and macerated with solvent (methanol or chloroform) for 24 h. The solvent was then eliminated along rotavapor. The yield of plant extract varied between 1.56 and 6.7%. Kinetics of growth of the 3 pathogens cultivable in liquid medium was determined before testing the impact of plant extracts and essential oils. Methanolic and chloroform plant extracts (EM1, EM2, EC1 and EC2) and essential oils (EO1, EO2) were compared for their antifungal potential. The chemical composition of the essential oils obtained by hydrodistillation from the aerial parts was analyzed by GC/MS. Yield of essential oil varied between 0.7 and 1.2%. Therefore, antifungal activity of plant extracts and essential oils was evaluated using ELISA microplates with a blocked randomized design, as described previously (Parisi et al., 2013). The results obtained showed that EM2 at 7 mg/ml has a very high fungistatic activity against Fusarium culmorum, F. oxysporum and Penicillium italicum. It was characterized with a high amount of polyphenols, flavonoids and condensed tannins. Statistical analysis showed that the efficiency of methanol extracts significantly differed from those of the chloroform extracts. In addition, essential oils significantly reduced spores germination in a dose-dependent manner. Their fungistatic activity reached 100% at 6000 ppm. In conclusion, this work allowed us to open new perspectives on the application of extremophile plant extracts as novel biocontrol strategy against plant pathogens. [less ▲]

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See detailNew elicitors to protect winter wheat against Zymoseptoria tritici?
Le Mire, Géraldine ULg; Jijakli, Haissam ULg; Siah, Ali et al

Conference (2016, September)

Today, focus is made on the crucial protection of wheat, as one of the most cultivated crop plants in the world. This crop is constantly challenged by a persistent and harmful fungus known as Zymoseptoria ... [more ▼]

Today, focus is made on the crucial protection of wheat, as one of the most cultivated crop plants in the world. This crop is constantly challenged by a persistent and harmful fungus known as Zymoseptoria tritici, responsible of the Septoria Tritici Blotch (STB) disease. Control of this disease mainly depends on chemical products. However there is an urgentneed to identify and develop alternative methods as biocontrol tools to adopt an efficient IPM program for wheat. Elicitors are increasingly considered as promising biocontrol tools in the preventive treatment of plants against various diseases. These plant-immunity triggering compounds, also called “stimulators of plant natural defenses”, induce a general and systemic resistance of the plant to a large spectrum of biotic stresses. This study focuses on the screening of nine molecules of various origins and structures for their potential eliciting activity, to protect winter wheat against Zymoseptoria tritici. The protective efficacy of these molecules was evaluated under greenhouse conditions by comparing the infection severity of the treated plants with a water control. In addition, the biocide activity of the 9 candidates was tested in vitro directly towards the pathogen, by evaluating their impact on spore germination and fungal growth. Finally, the qPFD tool developed by INRA was used to study the expression of 23 defense genes in the wheat plant following the various treatments. These combined experiments finally allowed the selection of two molecules as potent elicitors: EGL1 and EGL4. They were efficient to reduce foliar disease symptoms from 60 to 80% on wheat under greenhouse conditions. The efficacy of these 2 promising molecules was thus evaluated in 2 field trials in 2016. The corresponding results will be presented and discussed, with the perspective to investigate the efficacy of these 2 potent elicitors to protect wheat cultivars showing different levels of sensitivity towards the pathogen. [less ▲]

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See detailInsights gained from metagenomic sequencing of apple fruit surface (cv. Pinova)
Angeli, Dario; Massart, Sébastien ULg; Sare, Abdoul Razack ULg et al

Poster (2016, May 17)

Plant microbial communities (microbiota) living at the surface of fruit have been the source of the majority of biocontrol agents (BCAs). Despite this interest, their role as a community has been poorly ... [more ▼]

Plant microbial communities (microbiota) living at the surface of fruit have been the source of the majority of biocontrol agents (BCAs). Despite this interest, their role as a community has been poorly studied so far. They holistic study was an unattainable objective due to the absence of techniques to survey microbial communities and their evolution. The recent developments in high-throughput sequencing (HTS) have now enabled the holistic analysis of the microbiota genomes. A pioneering assay has been carried out to get insight into the microbiota of apple surface through metagenome sequencing. Apple from Pinova cultivar have been sampled in orchard and the microbiota isolated. After DNA extraction, the HTS assay generated 14.5 Gbases which were assembled in 133,888 contigs. These contigs provided useful information on taxonomic composition of the microbiota. A total of 1398 bacterial species and 397 fungal species have been identified. Among them, 22 species corresponded to known apple pathogens (Penicillium expansum, Penicillium spp, Botrytis cinerea, Monilinia fructicola, Nectria haematococca, Glomerella cingulate, G. graminicola, Alternaria alternate, Alternaria brassicicola, A. citri, A. longipes, A. solani, A. tenuissima, Fusarium solani, F. oxysporum, F. culmorum, F. lateritium, Mucor circinelloides, M. hiemalis, F. racemosus, Venturia inaequalis, Cladosporium cladosporioides). In addition, several contigs were assigned to species or genus of known BCA strains like Pichia canadensis, Bacillus sp., Debaryomyces hansenii, Aureobasidium pullulans and Pantoea vagans. These results will be discussed. In any case, these results underline a very diverse microbial community whose role needs to be characterized. In this line, the functional analysis (gene function determination) of the contigs is ongoing. [less ▲]

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