Personne :
Antoun, Hani

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Université Laval. Département des sols et de génie agroalimentaire
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Voici les éléments 1 - 10 sur 23
  • Publication
    Potential of Rhizobium and Bradyrhizobium species as plant growth promoting rhizobacteria on non-legumes: Effect on radishes (Raphanus sativus L.)
    (M. Nijhoff, 1998-01-01) Antoun, Hani; Beauchamp, Chantal Jeanne; Goussard, Nadia.; Chabot, Rock.; Lalande, Roger
    Bradyrhizobia and rhizobia are symbiotic bacterial partners forming nitrogen fixing nodules on legumes. These bacteria share characteristics with plant growth promoting rhizobacteria (PGPR). Nodule inducing bacteria, like other PGPR, are capable of colonizing the roots of non-legumes and produce phytohormones, siderophores and HCN. They also exhibit antagonistic effects towards many plant pathogenic fungi. The potential of nodule inducing bacteria to function as PGPR, was examined by using radish as a model plant. Three percent of the 266 strains tested were found to be cyanogens, while a majority (83%) produced siderophores. Fifty eight percent of the strains produced indole 3-acetic acid (IAA) and 54% solubilized phosphorus. Some of the bacterial species examined were found to have a deleterious effect while others were neutral or displayed a stimulatory effect on radishes. Bradyrizobium japonicum strain Soy 213 was found to have the highest stimulatory effect (60%), and an arctic strain (N44) was the most deleterious, causing a 44% reduction in radish dry matter yield. A second plant inoculation test, performed in growth cabinets, revealed that only strain Tal 629 of B. japonicum significantly increased (15%) the dry matter yield of radish. This indicates that specific bradyrhizobia have the potential to be used as PGPR on non-legumes.
  • Publication
    Accès libre
    Potential use of leachate from composted fruit and vegetable waste as fertilizer for corn
    (Taylor & Francis, 2019-02-08) Antoun, Hani; Beauchamp, Chantal Jeanne; Sall, Papa Malick; Chalifour, François-Philippe
    Composting fruit and vegetable waste from grocery stores on farms is a challenge due to the large quantity of liquid that leaches out. This leachate needs to be characterized for its effects on plant growth and soil. It was acidic with high conductivity; the plant mineral nutrient contents derived from the leachate (in decreasing order) were K, N mainly as ammonium-N, Ca, Mg, Na, and P; the trace elements were quite low. The germination and rootlet growth of cress and corn increased with the dilution of the compost leachate. In greenhouse assays, the compost leachate exhibited phytotoxicity to corn when used at high application rates. The corn leaf area, shoot and root biomass, plant concentrations and uptake of N, P and K were similar among the 20 mM N-fertilized control and the 30–40 m3/ha leachate treatments. In a field study on sandy loam, corn yields and plant uptake of P and K were similar among the mineral fertilized control and split-application leachate treatments applied to meet the P or K requirements of corn. After harvest, the soil pH, conductivity, and total N, P, and K contents were not affected by the leachate treatments. These results demonstrate the opportunity of recycling plant nutrients from compost leachate of fruit and vegetable waste as fertilizer to meet crop nutrient requirements without phytotoxicity and trace elements threats.
  • Publication
    Accès libre
    Insecticidal effect of Bacillus pumilus PTB180 and Bacillus subtilis PTB185 used alone and in combination against the foxglove aphid and the melon aphid (Hemiptera: Aphididae)
    (Cambridge University Press, 2021-09-10) McCune, Frédéric; Antoun, Hani; Nguyen, Thi Thuy An; Naasz, Rémi; Kahia, Mouna; Fournier, Valérie
    The foxglove aphid, Aulacorthum solani (Kaltenbach) (Hemiptera: Aphididae), and the melon aphid, Aphis gossypii Glover (Hemiptera: Aphididae), are among the serious insect pests found in greenhouses. The efficacy of microbial control against these insects has been demonstrated and can be enhanced by the combination of different microbial agents. This study evaluated the efficacy of Bacillus pumilus Meyer and Gottheil PTB180 and Bacillus subtilis (Ehrenberg) Cohn PTB185, used alone and together, to control these two aphids both in the laboratory and in greenhouse on tomato, Solanum lycopersicum Linnaeus (Solanaceae), and cucumber, Cucumis sativus Linnaeus (Cucurbitaceae), plants. The results from the laboratory tests showed an increase in mortality induced by all biological treatments. In the greenhouse, all treatments induced mortality rates significantly higher than that of the control for A. solani. Similarly, all treatments performed better than the control against A. gossypii, significantly reducing its reproduction. Furthermore, we found no additive effects when mixing products nor negative interactions affecting survival for the bacteria investigated. These microorganisms therefore have potential for use in biological control.
  • Publication
    Accès libre
    Influence of nitrogen sources and plant growth-promoting rhizobacteria Inoculation on growth, crude fiber and nutrient uptake in squash (cucurbita moschata duchesne ex poir.) plants
    (Academic Press, 2016-05-14) Tchiaze, Alice I.; Antoun, Hani; Taffouo, Victor D.; Baziramakenga, Régis; Lallier, Henri; Kenne, Martin; Ekodeck, Georges Emmanuel
    Plant growth promoting rhizobacteria (PGPR, B) have immense potential application in sustainable agriculture as ecofriendly biofertilizers and biopesticides. In this study, the effects of three nitrogen (N) sources (NO3-, NH4+ and NO3NH4) and PGPR on growth, crude fiber and nutrient uptake were investigated in squash plants. Some growth parameters [root dry weight (RDW), shoot dry weight (SDW), total plant dry weight (PDW), number of leaves (NL), shoot length (SL), stem diameter (SD) and number of ramifications (NR)], crude fiber (cellulose content) and nutrient uptake (N, P, K, Ca, Mg, Na, Fe, Cu, Mn and Zn) were determined. Application of NO3-, NH4+ or NO3NH4 singly or in combination with PGPR inoculation led to a significant increase in RDW, SDW, PDW, NL, SL, SD and NR. Na, Cu and Zn contents, on the contrary, decreased in inoculated treated plants while no significant differences were recorded in cellulose contents (CE) of leaves except in plants fed with NO3-. The leaf CE content ranged from 12.58 to 13.67%. The plants supplied with NO3+B, NH4+B and NO3NH4+B showed significantly higher plant biomass and accumulation of N, P, K and Mn concentrations in leaves compared to all other treatments. These results suggest that specific combinations of PGPR with NO3-, NH4+ or NO3NH4 fertilizers can be considered as efficient alternative biofertilizers to improve significantly the squash growth and nutrient uptake.
  • Publication
    Accès libre
    Igneous phosphate rock solubilization by biofilm-forming mycorrhizobacteria and hyphobacteria associated with Rhizoglomus irregulare DAOM 197198
    (Springer, 2016-08-19) Piché, Yves; St-Arnaud, Marc; Antoun, Hani; Fortin, J. A.; Taktek, Salma
    Biofilm formation on abiotic and biotic surfaces was studied with two hyphobacteria, strongly attached to the surface of the arbuscular mycorrhizal fungus (AMF) Rhizoglomus irregulare (Ri) DAOM 197198 and two mycorrhizobacteria, loosely attached to the roots of different mycorrhizal plants. When the sparingly soluble igneous phosphate rock (PR) from Quebec, or when the chemical hydroxyapatite were used as sole phosphorus (P) source, hyphobacteria Rhizobium miluonense Rm3 and Burkholderia anthina Ba8 produced significantly more biofilms than mycorrhizobacteria Rahnella sp. Rs11 and Burkholderiaphenazinium Bph12, as indicated by the crystal violet assay or by quantifying biofilm exopolysaccharides. As previously observed with planktonic bacteria, biofilms mobilized P by lowering the pH and releasing gluconic acid. The high efficiency of P mobilization by the hyphobacteria Ba8 was linked to the presence of more viable cells in its biofilm as revealed by the hydrolysis of fluorescein diacetate. Scanning electron microscopy micrographs showed a high adherence of the best P-solubilizer hyphobacteria Ba8 on the surface of Quebec PR. Hydroxyapatite porous structure did not allow a good adherence of Ba8. Ba8 formed an important biofilm on the hyphae of Ri DAOM 197198 with low reactive Quebec PR while no biofilm was observed with the high reactive hydroxyapatite. Results confirm the possible presence of specificity between the Ri DAOM 197198 and the hyphobacteria and suggest that the interaction would be regulated by the availability of P.
  • Publication
    Accès libre
    Microarray transcriptional profiling of Arctic Mesorhizobium strain N33 at low temperature provides insights into cold adaption strategies
    (BioMed Central, 2015-05-15) Antoun, Hani; Klein, Anne; Laberge, Serge; Ghobakhlou, Abdollah
    Background Arctic Mesorhizobium strain N33 was isolated from nodules of the legume Oxytropis arctobia in Canada’s eastern Arctic. This symbiotic bacterium can grow at temperatures ranging from 0 to 30 °C, fix nitrogen at 10 °C, and is one of the best known cold-adapted rhizobia. Despite the economic potential of this bacterium for northern regions, the key molecular mechanisms of its cold adaptation remain poorly understood. Results Using a microarray printed with 5760 Arctic Mesorhizobium genomic clones, we performed a partial transcriptome analysis of strain N33 grown under eight different temperature conditions, including both sustained and transient cold treatments, compared with cells grown at room temperature. Cells treated under constant (4 and 10 °C) low temperatures expressed a prominent number of induced genes distinct from cells treated to short-term cold-exposure (<60 min), but exhibited an intermediate expression profile when exposed to a prolonged cold exposure (240 min). The most prominent up-regulated genes encode proteins involved in metabolite transport, transcription regulation, protein turnover, oxidoreductase activity, cryoprotection (mannitol, polyamines), fatty acid metabolism, and membrane fluidity. The main categories of genes affected in N33 during cold treatment are sugar transport and protein translocation, lipid biosynthesis, and NADH oxidoreductase (quinone) activity. Some genes were significantly down-regulated and classified in secretion, energy production and conversion, amino acid transport, cell motility, cell envelope and outer membrane biogenesis functions. This might suggest growth cessation or reduction, which is an important strategy to adjust cellular function and save energy under cold stress conditions. Conclusion Our analysis revealed a complex series of changes associated with cold exposure adaptation and constant growth at low temperatures. Moreover, it highlighted some of the strategies and different physiological states that Mesorhizobium strain N33 has developed to adapt to the cold environment of the Canadian high Arctic and has revealed candidate genes potentially involved in cold adaptation.
  • Publication
    Accès libre
    Promotion au champ, de la croissance, l’absorption du phosphore et le rendement de maïs (Zea mays) par les souches de Bacillus isolées des sols du Mali et solubilisant le Phosphate Naturel de Tilemsi
    (2013-01-01) Traoré, Lamine; Antoun, Hani; Babana, Amadou Hamadoun; Sacko, O.; Yattara, Inamoud Ibny; Lahbib, Messaoud
    La carence de phosphore (P) est l’un des principaux facteurs limitant la production agricole au Mali. Les cultures répondent bien à la fertilisation phosphatée, mais le coût élevé des engrais chimiques importés restreint leur utilisation par les agriculteurs. Cependant, dans la vallée de Tilemsi, le Mali dispose de gisements de phosphates estimés entre 20 à 25 millions de tonnes, avec une teneur en P2O5 de l’ordre de 23 % à 30 %. Dans le but d’améliorer biologiquement l’absorption de phosphore par le maïs fertilisé avec du phosphate naturel de Tilemsi (PNT), l’effet de l’inoculation de souches de Bacillus isolées des sols maliens a été étudié. La croissance et la teneur en P de trois variétés de maïs ont été mesurées en 2007 ; la croissance, la teneur en P et le rendement de la variété de maïs Sotubaka ont été mesurés en 2008 dans des conditions de champ au Mali. L’expérimentation a été menée au cours des saisons agricoles de 2007 et 2008 à la station de recherche agronomique de Samanko située à 15 km au Sud-Ouest du District de Bamako au Mali. Elle est à une latitude de 12°. 31.552’ Nord, à une longitude de 8°.04.906’ Ouest et à une altitude de 316,8 m. Le sol est de type ferrugineux tropical peu lessivé, de texture limono sableuse avec 76 % de sable, 15 % de limon et 9 % d’argile (Labosep, IER, 2008). Un dispositif expérimental de type split- plit- plot à trois répétitions a été utilisé avec, en parcelles principales, la fertilisation (le PNT 300 kg/ha (insoluble), l’engrais chimique, le complexe céréale 100 kg/ha (17-17-17) et le témoin sans phosphore. Toutes les parcelles ont reçu la même quantité d’azote N équivalente à 150 kg d’urée. Les compléments N et K de l’engrais chimique ont été corrigés pour toutes les autres parcelles. Les parcelles secondaires étaient composées de trois variétés de maïs (Dembanyuman, Sotubaka, Tiémantié) et les parcelles tertiaires étaient composées de témoin non inoculé et les six inoculations avec les lignées de Bacillus solubilisant le PNT. Toutes les lignées appartiennent à Bacillus subtilis subsp. subtilis (T) ; DSM10. Nos résultats ont montré que la fertilisation phosphatée du maïs avec le PNT ou le complexe céréale (17-17-17) améliore significativement les rendements grain et de la biomasse sèche. L’inoculation avec les souches de bactéries solubilisant le PNT n’a pas influencé la taille des plants après 60 jours de croissance mais elle a significativement influencé l’absorption de P dans les grains et dans la biomasse aérienne sèche. La fertilisation du maïs avec le PNT et l’inoculation avec ces bactéries ont occasionné une plus grande teneur en phosphore des grains et de la biomasse sèche du maïs. La mycorrhization des racines de maïs par les champignons mycorrhiens indigènes a été déterminée en utilisant la méthode de Philips et Hyman (1970).
  • Publication
    Plant-growth-promoting rhizobacteria
    (Elsevier, 2013-05-01) Antoun, Hani
    About 2–5% of rhizobacteria, when present in large number, are able to promote plant growth. Production of plant hormones and improving mineral nutrition are examples of direct promotion, while protecting plants against many diseases caused by bacteria, fungi, viruses, nematodes, or insects is indirect mechanism of growth promotion.
  • Publication
    Accès libre
    Une méthode rapide de préselection des souches de Rhizobium meliloti
    (Agricultural Institute of Canada., 1978-10-04) Bordeleau, Lucien M.; Antoun, Hani
    On a étudie le pH final des cultures pures de 49 souches de Rhizobium meliloti comme moyen rapide d’évaluation de leur efficacité symbiotique. Il existe une corrélation positive et très significative entre le pH final et l’efficacité des souches. Cette méthode peut être utilisée comme moyen simple et rapide de présélection d’un grand nombre d’isolats de R. meliloti.
  • Publication
    Accès libre
    Metabolomic analysis of cold acclimation of arctic mesorhizobium sp. strain N33
    (Public Library of Science, 2013-12-30) Antoun, Hani; Laberge, Serge; Ghobakhlou, Abdollah; Wishart, David Scott; Xia, Jianguo; Krishnamurthy, Ramanarayan; Mandal, Rupasri
    Arctic Mesorhizobium sp. N33 isolated from nodules of Oxytropis arctobia in Canada’s eastern Arctic has a growth temperature range from 0°C to 30°C and is a well-known cold-adapted rhizobia. The key molecular mechanisms underlying cold adaptation in Arctic rhizobia remains totally unknown. Since the concentration and contents of metabolites are closely related to stress adaptation, we applied GC-MS and NMR to identify and quantify fatty acids and water soluble compounds possibly related to low temperature acclimation in strain N33. Bacterial cells were grown at three different growing temperatures (4°C, 10°C and 21°C). Cells from 21°C were also cold-exposed to 4°C for different times (2, 4, 8, 60 and 240 minutes). We identified that poly-unsaturated linoleic acids 18∶2 (9, 12) & 18∶2 (6, 9) were more abundant in cells growing at 4 or 10°C, than in cells cultivated at 21°C. The mono-unsaturated phospho/neutral fatty acids myristoleic acid 14∶1(11) were the most significantly overexpressed (45-fold) after 1hour of exposure to 4°C. As reported in the literature, these fatty acids play important roles in cold adaptability by supplying cell membrane fluidity, and by providing energy to cells. Analysis of water-soluble compounds revealed that isobutyrate, sarcosine, threonine and valine were more accumulated during exposure to 4°C. These metabolites might play a role in conferring cold acclimation to strain N33 at 4°C, probably by acting as cryoprotectants. Isobutyrate was highly upregulated (19.4-fold) during growth at 4°C, thus suggesting that this compound is a precursor for the cold-regulated fatty acids modification to low temperature adaptation.