The Experts below are selected from a list of 1761 Experts worldwide ranked by ideXlab platform
Jijakli Haissam - One of the best experts on this subject based on the ideXlab platform.
-
L'eau aquponique, une nouvelle source d'agents de biocontrôle contre la pourriture racinaire des laitues causée par Pythium aphanidermatum
2020Co-Authors: Stouvenakers Gilles, Massart Sébastien, Jijakli HaissamAbstract:audience: researcher, professional, student, popularization, otherIn aquaponics, phytosanitary treatments for plant diseases management are a delicate matter because of the presence of fish. However, it appears that aquaponic systems could be naturally armed against plant pathogens. This natural protective action is called suppressiveness. Aquaponic water has shown a direct inhibitory effect on in vitro Pythium spp. growth (Gravel et al. 2015; Sirakov et al. 2016; Stouvenakers et al. 2018). To confirm this discovery, in vivo experiments using Pythium aphanidermatum have been carried out on lettuces growing in hydroponic (HP) water, aquaponic (AP) water or aquaponic water complemented (COMP) with mineral nutrients to reach HP levels. Suppressiveness property of AP, COMP and HP waters was evaluated by comparing root symptoms and lettuces yields. For each treatments, lettuces root microbiota were analysed after Illumina high throughput sequencing of ITS and 16S rDNA genes. Results showed that yields and roots health of AP lettuces were significantly better compared to COMP and HP lettuces. The bioinformatics analysis of sequenced microbiota showed differences in terms of microbiota diversity and features composition when comparing AP with COMP and HP water. These results highlight that the physicochemical modifications of the AP water to make the COMP water disturb the AP microbiota and lead to the loss of its suppressive capacity. Moreover, AP could be an interesting source of novel biocontrol agents for plant pathogens control in aquaponics
-
L'eau aquponique, une nouvelle source d'agents de biocontrôle contre la pourriture racinaire des laitues causée par Pythium aphanidermatum
2020Co-Authors: Stouvenakers Gilles, Massart Sébastien, Jijakli HaissamAbstract:In aquaponics, phytosanitary treatments for plant diseases management are a delicate matter because of the presence of fish. However, it appears that aquaponic systems could be naturally armed against plant pathogens. This natural protective action is called suppressiveness. Aquaponic water has shown a direct inhibitory effect on in vitro Pythium spp. growth (Gravel et al. 2015; Sirakov et al. 2016; Stouvenakers et al. 2018). To confirm this discovery, in vivo experiments using Pythium aphanidermatum have been carried out on lettuces growing in hydroponic (HP) water, aquaponic (AP) water or aquaponic water complemented (COMP) with mineral nutrients to reach HP levels. Suppressiveness property of AP, COMP and HP waters was evaluated by comparing root symptoms and lettuces yields. For each treatments, lettuces root microbiota were analysed after Illumina high throughput sequencing of ITS and 16S rDNA genes. Results showed that yields and roots health of AP lettuces were significantly better compared to COMP and HP lettuces. The bioinformatics analysis of sequenced microbiota showed differences in terms of microbiota diversity and features composition when comparing AP with COMP and HP water. These results highlight that the physicochemical modifications of the AP water to make the COMP water disturb the AP microbiota and lead to the loss of its suppressive capacity. Moreover, AP could be an interesting source of novel biocontrol agents for plant pathogens control in aquaponics
J C Sutton - One of the best experts on this subject based on the ideXlab platform.
-
controle biologico da podridao radicular Pythium aphanidermatum e promocao de crescimento por pseudomonas chlororaphis 63 28 e bacillus subtilis gb03 em alface hidroponica
Summa Phytopathologica, 2010Co-Authors: Elida Barbosa Correa, Wagner Bettiol, J C SuttonAbstract:Podridoes radiculares causadas por especies de Pythium sao um importante problema em cultivos hidroponicos. Sintomas de subdesenvolvimento sao observados nas plantas parasitadas pelo patogeno, sendo muitas vezes nao diagnosticados pelo produtor. O objetivo do trabalho foi avaliar o controle biologico da podridao radicular causada por Pythium aphanidermatum e a promocao de crescimento por Pseudomonas chlororaphis 63-28 e Bacillus subtilis GB03, reconhecidos agentes de controle biologico de doencas de plantas. A inoculacao das plantas com P. aphanidermatum ocasionou o subdesenvolvimento, sendo essa diminuicao de 20%. A adicao dos agentes de biocontrole na solucao nutritiva teve um efeito positivo no aumento da massa (6% a 13%), no numero de folhas (4% a 7%) e no teor de clorofila (3%) das plantas de alface. Entretanto, maiores estudos devem ser realizados para melhorar a capacidade de controle da doenca e de promocao de crescimento pelos agentes de biocontrole estudados no cultivo de alface hidroponica.
-
timing pseudomonas chlororaphis applications to control Pythium aphanidermatum Pythium dissotocum and root rot in hydroponic peppers
Biological Control, 2004Co-Authors: Syama Chatterton, J C Sutton, G J BolandAbstract:Abstract The ability of the microbial agent Pseudomonas (Ps.) chlororaphis Tx-1 to suppress Pythium aphanidermatum and Pythium dissotocum, and control root rot, was investigated as a function of time of agent application and pathogen inoculation in vegetative-stage sweet peppers grown in single-plant hydroponic units. The agent was applied to the nutrient solution at 1× 107 CFU/mL and roots were inoculated by immersion in suspensions of 5 × 103 or 1 × 104 zoospores/mL. When Ps. chlororaphis was applied at 14, 7, 3, or 0 days before roots were inoculated with P. aphanidermatum, treatments timed as follows were significantly, and often markedly, effective: 3 and 0 days against root colonization by the pathogen; 14, 7, and 3 days against brown root tips; and 7, 3, and 0 days against percent discolored roots. In a parallel study of P. dissotocum, each treatment suppressed symptoms, though inconsistently, but not colonization. When Ps. chlororaphis was applied once (day 0) or twice (days 0 and 14) and roots were inoculated with P. aphanidermatum on day 3 or day 17, the single treatment strongly suppressed colonization, brown root tips and percent colonization regardless of inoculation time, but the second treatment did not improve control. Density of Ps. chlororaphis associated with the roots after one or two applications, respectively, ranged up to 1.3–1.5 × 105 and 8.0 × 106–1.6 × 107 CFU/g fresh roots. The density rapidly declined in noninoculated roots but generally remained high in roots inoculated with either pathogen. Collectively, the observations suggest that Ps. chlororaphis treatments should be timed to maintain about 105 CFU of the agent/g fresh roots, that more frequent application is needed to maintain the agent in healthy compared to infected roots, and that an ideal time for initial application is 3 days before an attack by P. aphanidermatum or P. dissotocum.
-
effects of pseudomonas chlororaphis on Pythium aphanidermatum and root rot in peppers grown in small scale hydroponic troughs
Biocontrol Science and Technology, 2003Co-Authors: A Khan, J C Sutton, B GrodzinskiAbstract:The ability of Pseudomonas (Ps.) chlororaphis isolate Tx-1 to suppress Pythium aphanidermatum and control root rot was investigated in sweet peppers grown in small-scale hydroponic trough units with recirculating nutrient solution. The agent was introduced to the nutrient solution 3 days after the peppers were inoculated with P. aphanidermatum, or 4 days before and 3 days after inoculation, or 4 days before and 3 and 10 days after. Controls either received no agent or pathogen, or the agent only (applied once, 4 days before the time of pathogen inoculations), or the pathogen only. The experiment was conducted in a greenhouse with repetitions beginning in January, March, and May. Severity of root browning associated with P. aphanidermatum, in the absence of Ps. chlororaphis, increased in the first, second and third repetitions, respectively, to 74% at 21 days, 28% at 21 days, and 68% at 11 days. In treatments with one, two, or three applications of Ps. chlororaphis, respectively, areas under root browning ...
-
interactions among Pythium aphanidermatum roots root mucilage and microbial agents in hydroponic cucumbers
Canadian Journal of Plant Pathology-revue Canadienne De Phytopathologie, 2000Co-Authors: J Zheng, J C SuttonAbstract:Epidemics and biological control of Pythium root rot were investigated in greenhouse cucumbers grown in small-scale hydroponic systems with troughs and recirculating nutrient solution. The systems were inoculated with Pythium aphanidermatum only or with the pathogen plus an isolate of Pseudomonas fluorescens or Pseudomonas chlororaphis. In systems with P. aphanidermatum only, growth rate of roots, amount of root mucilage in the nutrient solution, and root discoloration (browning) oscillated in patterns that were generally similar and synchronous. These variables abruptly increased for 6-14 days, starting at about 21 days after transplanting, subsequently declined to low levels at 41-56 days, and then increased again starting at 53-61 days. Logarithm to the base 10 of propagule density of P aphanidermatum usually was several orders higher in the mucilage (2.09-4.90/g) than in the nutrient solution (0.25-2.67/mL). The pathogen was also more frequent in roots with associated mucilage (14-60 colonies/60 cm of...
Stouvenakers Gilles - One of the best experts on this subject based on the ideXlab platform.
-
L'eau aquponique, une nouvelle source d'agents de biocontrôle contre la pourriture racinaire des laitues causée par Pythium aphanidermatum
2020Co-Authors: Stouvenakers Gilles, Massart Sébastien, Jijakli HaissamAbstract:audience: researcher, professional, student, popularization, otherIn aquaponics, phytosanitary treatments for plant diseases management are a delicate matter because of the presence of fish. However, it appears that aquaponic systems could be naturally armed against plant pathogens. This natural protective action is called suppressiveness. Aquaponic water has shown a direct inhibitory effect on in vitro Pythium spp. growth (Gravel et al. 2015; Sirakov et al. 2016; Stouvenakers et al. 2018). To confirm this discovery, in vivo experiments using Pythium aphanidermatum have been carried out on lettuces growing in hydroponic (HP) water, aquaponic (AP) water or aquaponic water complemented (COMP) with mineral nutrients to reach HP levels. Suppressiveness property of AP, COMP and HP waters was evaluated by comparing root symptoms and lettuces yields. For each treatments, lettuces root microbiota were analysed after Illumina high throughput sequencing of ITS and 16S rDNA genes. Results showed that yields and roots health of AP lettuces were significantly better compared to COMP and HP lettuces. The bioinformatics analysis of sequenced microbiota showed differences in terms of microbiota diversity and features composition when comparing AP with COMP and HP water. These results highlight that the physicochemical modifications of the AP water to make the COMP water disturb the AP microbiota and lead to the loss of its suppressive capacity. Moreover, AP could be an interesting source of novel biocontrol agents for plant pathogens control in aquaponics
-
L'eau aquponique, une nouvelle source d'agents de biocontrôle contre la pourriture racinaire des laitues causée par Pythium aphanidermatum
2020Co-Authors: Stouvenakers Gilles, Massart Sébastien, Jijakli HaissamAbstract:In aquaponics, phytosanitary treatments for plant diseases management are a delicate matter because of the presence of fish. However, it appears that aquaponic systems could be naturally armed against plant pathogens. This natural protective action is called suppressiveness. Aquaponic water has shown a direct inhibitory effect on in vitro Pythium spp. growth (Gravel et al. 2015; Sirakov et al. 2016; Stouvenakers et al. 2018). To confirm this discovery, in vivo experiments using Pythium aphanidermatum have been carried out on lettuces growing in hydroponic (HP) water, aquaponic (AP) water or aquaponic water complemented (COMP) with mineral nutrients to reach HP levels. Suppressiveness property of AP, COMP and HP waters was evaluated by comparing root symptoms and lettuces yields. For each treatments, lettuces root microbiota were analysed after Illumina high throughput sequencing of ITS and 16S rDNA genes. Results showed that yields and roots health of AP lettuces were significantly better compared to COMP and HP lettuces. The bioinformatics analysis of sequenced microbiota showed differences in terms of microbiota diversity and features composition when comparing AP with COMP and HP water. These results highlight that the physicochemical modifications of the AP water to make the COMP water disturb the AP microbiota and lead to the loss of its suppressive capacity. Moreover, AP could be an interesting source of novel biocontrol agents for plant pathogens control in aquaponics
Salme Timmusk - One of the best experts on this subject based on the ideXlab platform.
-
paenibacillus polymyxa antagonizes oomycete plant pathogens phytophthora palmivora and Pythium aphanidermatum
Journal of Applied Microbiology, 2009Co-Authors: Salme Timmusk, Pieter Van West, Neil A. R. Gow, Paul R HuffstutlerAbstract:Aim: To find sustainable alternatives to the application of synthetic chemicals for oomycete pathogen suppression. Methods and Results: Here, we present experiments on an Arabidopsis thaliana model system in which we studied the antagonistic properties of rhizobacterium Paenibacillus polymyxa strains towards the oomycete plant pathogens Phytophthora palmivora and Pythium aphanidermatum. We carried out studies on agar plates, in liquid media and in soil. Our results indicate that P. polymyxa strains significantly reduced P. aphanidermatum and P. palmivora colonization in liquid assays. Most plants that had been treated with P. polymyxa survived the P. aphanidermatum inoculations in soil assays. Conclusions: The antagonistic abilities of both systems correlated well with mycoidal substance production and not with the production of antagonistic substances from the biocontrol bacteria. Significance and Impact of the Study: Our experiments highlight the need to take biofilm formation and niche exclusion mechanisms into consideration for biocontrol assays performed under natural conditions.
-
Antagonistic effects of Paenibacillus polymyxa towards the oomycete plant pathogens Phytophthora palmivora and Pythium aphanidermatum
2003Co-Authors: Salme Timmusk, Pieter Van West, Neil A. R. Gow, Gerhart E. H. WagnerAbstract:Antagonistic effects of Paenibacillus polymyxa towards the oomycete plant pathogens Phytophthora palmivora and Pythium aphanidermatum
Stephen P. Wraight - One of the best experts on this subject based on the ideXlab platform.
-
Fungus gnat feeding and mechanical wounding inhibit Pythium aphanidermatum infection of geranium seedlings.
Phytopathology®, 2009Co-Authors: S. E. Braun, John P. Sanderson, E. B. Nelson, Margery L. Daughtrey, Stephen P. WraightAbstract:Braun, S. E., Sanderson, J. P., Nelson, E. B., Daughtrey, M. L., and Wraight, S. P. 2009. Fungus gnat feeding and mechanical wounding inhibit Pythium aphanidermatum infection of geranium seedlings. Phytopathology 99:1421-1428. A series of laboratory tests were conducted to investigate potential effects of fungus gnat (Bradysia impatiens) feeding damage on susceptibility of geranium seedlings (Pelargonium × hortorum) to infection by the root rot pathogen Pythium aphanidermatum. Effects were compared with those from similar tests in which the seedlings were mechanically wounded by severing the root tip with a scalpel. Assays of geranium seedlings in petri dishes revealed a pronounced negative fungus gnat–Pythium interaction, with exposure to fungus gnat larvae 24 h prior to inoculation with P. aphanidermatum zoospores resulting in up to 47% fewer seedling deaths than would have been expected if the two agents had acted independently. Similar results were observed when seedlings were subjected to mechanical wounding 24 h prior to zoospore inoculation. In contrast, no interaction occurred when seedlings were mechanically wounded immediately prior to inoculation. The degree of plant damage inflicted by the feeding activities of the larval fungus gnats had no significant effect on the combined damage from fungus gnats and Pythium in petri dishes. Ancillary studies showed that Pythium development on V8 agar was not inhibited by the presence of fungus gnatassociated microorganisms, nor were seedlings inoculated with these microbes less susceptible to Pythium infection. The precise mechaism or mechanisms underlying the observed interactions were not elucidated; however, the results strongly suggest that both fungus gnat feeding and mechanical wounding activated systemic defenses that made the seedlings more resistant to Pythium infection.
