References of "Spaepen, Stijn"
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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 detailEffects of Plant Growth-Promoting Rhizobacteria on Wheat Growth under Greenhouse and Field Conditions in combination with different nitrogen fertilizer levels
Nguyen, Minh ULg; Ongena, Marc ULg; Colinet, Gilles ULg et al

Poster (2015, November 23)

Many Plant Growth-Promoting Rhizobacteria (PGPR) are able to enhance root growth, mineral availability, and nutrient use efficiency of crops. The aim of this project is to screen commercially available ... [more ▼]

Many Plant Growth-Promoting Rhizobacteria (PGPR) are able to enhance root growth, mineral availability, and nutrient use efficiency of crops. The aim of this project is to screen commercially available PGPR formulations and lab strains to increase wheat growth and yield in combination with an optimized nitrogen (N) fertilizer application scheme. This could lead to a significant reduction of N fertilizer application without affecting the subsequent grain yields. The screened products collection includes (1) Mix1 (a mix of Azospirillum sp., Azorhizobium sp., and Azoarcus sp.), (2) Mix2 (a mix of Mix1 complemented with two strains of phosphorus-solubilizing Bacillus sp.), (3) Bacillus amyloliquefaciens a, (4) B. subtilis, and (5) B. amyloliquefaciens b. These products were screened under greenhouse and field conditions in 2014 by using spring and winter wheat varieties, respectively. Under greenhouse conditions, there was a significant increase in root dry weight and in root per shoot ratio of plants inoculated with Mix1. Under field conditions, the interaction between PGPR inoculation and different N fertilizer doses was assessed. The grain yield was negatively impacted by low N fertilizer applications. Under such conditions, the inoculation of the wheat rhizosphere with B. subtilis increased the grain yield by 15% relative to the water control. However, in the field trial, the variability between plot replicates was high and lead to non-significant results. Based on these results, modified screening strategies for PGPR selection were set up for the next trials. [less ▲]

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See detailImpacts of Plant Growth-Promoting Rhizobacteria-based Biostimulants on Wheat Growth under Greenhouse and Field Conditions
Nguyen, Minh ULg; Ongena, Marc ULg; Colinet, Gilles ULg et al

Poster (2015, November 16)

Plant Growth-Promoting Rhizobacteria (PGPR) are one of the main biostimulant classes due to their capacity of stimulating root growth and enhancing soil mineral availability, hence increasing nutrient use ... [more ▼]

Plant Growth-Promoting Rhizobacteria (PGPR) are one of the main biostimulant classes due to their capacity of stimulating root growth and enhancing soil mineral availability, hence increasing nutrient use efficiency in crops. The aim of this study is to screen commercially PGPR-containing products to enhance wheat growth and yield in combination with an optimized nitrogen (N) fertilizer application scheme. This could lead to a significant reduction of N fertilizer application without affecting the subsequent grain yields. The screened products collection includes (1) Mix1 (a mix of Azospirillum sp., Azorhizobium sp., and Azoarcus sp.), (2) Mix2 (a mix of Mix1 complemented with two strains of phosphorus-solubilizing Bacillus sp.), (3) Bacillus amyloliquefaciens a, (4) B. subtilis, and (5) B. amyloliquefaciens b. These biostimulants were screened under greenhouse and field conditions in 2014 by using spring and winter wheat varieties respectively. There was a significant increase in root dry weight and in root per shoot ratio of plants inoculated with Mix1. Under field conditions, the interaction between PGPR inoculation and N fertilizer application was assessed. The grain yield was negatively impacted by low N fertilizer applications. Under such conditions, the inoculation of the wheat rhizosphere with Bacillus subtilis increased the grain yield by 15% relative to the water control. However, in the field trial, the variability between plot replicates was high and lead to non-significant results. Based on those results, modified screening strategies for PGPR selection were set up for the 2015 trials to reduce field variability and possibly achieve higher yield increases. [less ▲]

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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 detailImpacts of Plant Growth-Promoting Rhizobacteria on Wheat Growth under Greenhouse and Field Conditions
Nguyen, Minh ULg; du Jardin, Patrick ULg; Jijakli, Haissam ULg et al

Poster (2015, June 16)

Plant Growth-Promoting Rhizobacteria (PGPR) are well-known on stimulating root growth, enhancing mineral availability, and nutrient use efficiency in crops, and therefore become promising tool for ... [more ▼]

Plant Growth-Promoting Rhizobacteria (PGPR) are well-known on stimulating root growth, enhancing mineral availability, and nutrient use efficiency in crops, and therefore become promising tool for sustainable agriculture. The aim of this project is to screen PGPR strains to enhance wheat growth and yield in combination with an optimised nitrogen (N) fertilizer dose, and thus finally reduce the use of N fertilizer with equivalent yield as the recommended N dose. A list of PGPR has been collected, including (1) Mix1 (a mix of Azospirillum sp., Azorhizobium sp., and Azoarcus sp.), (2) Mix2 (a mix of Mix1 plus with two strains phosphorus-solubilizing Bacillus sp.), (3) Bacillus amyloliquefaciens a, (4) Bacillus subtilis, and (5) Bacillus amyloliquefaciens b. The PGPR were screened in both greenhouse and field condition 2014. There was significant increase in root dry weight and in root per shoot ratio of plants inoculated with Mix1 in the greenhouse. Under field condition, besides the first factor PGPR, an additional factor, i.e. four N fertilizer doses, was applied in the combination with PGPR. Without or at low N fertilizer doses, the results showed that the grain yield declined significantly. The highest grain yield increase was fifteen per cent above the control and achieved by inoculating Bacillus subtilis without application of N fertilizer. However, there was statistically insignificant in all treatments due to variability between plot replicates. Based on these results, a modified protocol plus new strategies for PGPR selection has been built up for 2015 trial to reduce the influence of variability on field and possibly achieve the higher yield increase. [less ▲]

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See detailImpacts of biostimulant products on the growth of wheat and the microbial communities of its rhizosphere under contrasted production systems
Nguyen, Minh ULg; Bodson, Bernard ULg; Colinet, Gilles ULg et al

Poster (2014, August 24)

Plant growth-promoting rhizobacteria (PGPR) are one of the major biostimulant classes due to their ability to stimulate root growth, enhance mineral availability, and nutrient use efficiency in crops ... [more ▼]

Plant growth-promoting rhizobacteria (PGPR) are one of the major biostimulant classes due to their ability to stimulate root growth, enhance mineral availability, and nutrient use efficiency in crops. PGPR-containing biostimulant products could therefore make agriculture more sustainable by reducing demand for chemical fertilizer and lessen their negative environmental impacts. The aim of this project is to screen PGPR strains to (1) enhance wheat fitness level (growth, photosynthesis efficiency, stress tolerance, and yield) in combination with an optimised fertilizer level, (2) stimulate the increase in beneficial microorganism communities and suppress pathogenic ones in the wheat rhizosphere, (3) link wheat productivity to the composition of the microbial communities found in its rhizosphere, and (4) measure the impacts of such changes on soil fertility. A list of PGPR-containing biostimulants have been collected from screening, including several commercially available products (e.g. TwinN and NitroGuard, Mabiotec; Rhizocell GC, Ithec; B. subtilis FZB24 fl and Rhizo Vital 42, Abitep) as well as newly discovered PGPR strains. The biostimulants from that list have been screened in greenhouse and we expect to obtain results within next month. In parallel, several levels of nitrogen supply have been tested in combination with biostimulants to optimize agricultural practices and achieve the highest yield on field condition. A soil analysis protocols will also be built up to measure the influence of those PGPR strains on soil fertility changes and root uptake efficiency. In order to assess changes in the rhizomicrobial communities including fungi and bacteria (either pathogenic, neutral, or beneficial) under controlled or field conditions, metagenomic approaches will be set up. Finally, a maximum of three promising PGPR strains will be selected for practical agronomical application in larger field trials. [less ▲]

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See detailPlant growth- promoting rhizobacteria emit volatiles compounds with biostimulation activity in dicot and monocot plant species.
du Jardin, Patrick ULg; Delaplace, Pierre ULg; Varin, Sébastien et al

in Perata, Pierdomenico; Brown, Patrick; Ponchet, Michel (Eds.) Abstracts Book for Oral and Poster Presentations of the 1st World Congress on the use of Biostimulants in Agriculture (2012, November)

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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)

Detailed reference viewed: 20 (0 ULg)