Abstract:Sampling of agricultural soils from the Mexican northeastern region was performed to
detect Trichoderma spp., genetically characterize it, and assess its
potential use as a biologic control agent against Macrophomina
phaseolina. M. phaseolina is a phytopathogen that
attacks over 500 species of cultivated plants and causes heavy losses in the regional
sorghum crop. Sampling was performed immediately after sorghum or corn harvest in an
area that was approximately 170 km from the Mexico-USA border. Sixteen isolat… Show more
“…T. harzianum (Th-7), showed certain ability that may be associated to fungistatic effects, while T. koningiopsis (Tk NRRL50190) and T. asperellum (Ta NRRL50191) showed some fungicidal effects that were captured when hyphae and sporangia of the pathogen were parasitized by Tk and Ta hyphae. Similar results have been reported for T. koningiopsis against Macrophomina phaseolina (Hernández-Mendoza et al, 2015). Osorio-Hernández et al (2011) also reported 31 Mexican Trichoderma isolates with the ability to produce volatile compounds with inhibitory properties against P. capsici.…”
Phytophthora capsici is the main agent of chili pepper root rot, causing significant yield losses in commercial fields worldwide. Management of this plant pathogen has been difficult due to its ability to develop fungicide resistance, therefore biocontrol of P. capsici appears to be a promising alternative. In this study we evaluated the effects of three species of Trichoderma: T. harzianum (Th-7), T. koningiopsis (Tk NRRL50190) and T. asperellum (Ta NRRL50191) on two mexican isolates of P. capsici (RDP-1 and RDP-2) obtained from commercial pepper fields in Aguascalientes, Mexico. The ability to inhibit mycelia growth of P. capsici was tested with in vitro assays, followed by the quantification of sporangia after dual confrontations. All Trichoderma isolates inhibited the mycelia growth of the phytopathogen, but only Ta and Tk showed mycoparasitism. Sporangia production of P. capsici RDP-1 and RDP-2 was significantly reduced by Trichoderma isolates, compared to the non-confronted control, except for the Th-RDP-2 confrontation. Sporangia of RDP-1 significantly decreased by 95.6%, 81.3% and 78% after confrontations with Tk, Ta and Th, respectively; and by 76% and 85.4% in RDP-2 by Tk and Ta, respectively. The results suggest that Ta, Tk and Th could be used as potential biocontrol agents of Phytopthora root rot, however, further studies are necessary to test the in vivo protection of Ta, Tk and Th and their synergistic effects against Phytophthora root rot of chile peppers and other P. capsici susceptible solanaceous and cucurbitaceous crops such as tomatoes, squash, melons, and cucumbers.
“…T. harzianum (Th-7), showed certain ability that may be associated to fungistatic effects, while T. koningiopsis (Tk NRRL50190) and T. asperellum (Ta NRRL50191) showed some fungicidal effects that were captured when hyphae and sporangia of the pathogen were parasitized by Tk and Ta hyphae. Similar results have been reported for T. koningiopsis against Macrophomina phaseolina (Hernández-Mendoza et al, 2015). Osorio-Hernández et al (2011) also reported 31 Mexican Trichoderma isolates with the ability to produce volatile compounds with inhibitory properties against P. capsici.…”
Phytophthora capsici is the main agent of chili pepper root rot, causing significant yield losses in commercial fields worldwide. Management of this plant pathogen has been difficult due to its ability to develop fungicide resistance, therefore biocontrol of P. capsici appears to be a promising alternative. In this study we evaluated the effects of three species of Trichoderma: T. harzianum (Th-7), T. koningiopsis (Tk NRRL50190) and T. asperellum (Ta NRRL50191) on two mexican isolates of P. capsici (RDP-1 and RDP-2) obtained from commercial pepper fields in Aguascalientes, Mexico. The ability to inhibit mycelia growth of P. capsici was tested with in vitro assays, followed by the quantification of sporangia after dual confrontations. All Trichoderma isolates inhibited the mycelia growth of the phytopathogen, but only Ta and Tk showed mycoparasitism. Sporangia production of P. capsici RDP-1 and RDP-2 was significantly reduced by Trichoderma isolates, compared to the non-confronted control, except for the Th-RDP-2 confrontation. Sporangia of RDP-1 significantly decreased by 95.6%, 81.3% and 78% after confrontations with Tk, Ta and Th, respectively; and by 76% and 85.4% in RDP-2 by Tk and Ta, respectively. The results suggest that Ta, Tk and Th could be used as potential biocontrol agents of Phytopthora root rot, however, further studies are necessary to test the in vivo protection of Ta, Tk and Th and their synergistic effects against Phytophthora root rot of chile peppers and other P. capsici susceptible solanaceous and cucurbitaceous crops such as tomatoes, squash, melons, and cucumbers.
“…4). After 1 week, there was some growth at 1250 mM NH 4 -N for all T. harzianum strains meanwhile the typical green centric ring indicating conidia formation at maturity [31] could be seen only in petri dishes with NH 4 -N levels from 0 to 250 mM NH 4 -N. Therefore, whereas 250 mM NH 4 -N depressed vegetative growth only, the toxicity of 1250 mM inhibited both vegetative and generative growth. Penicillium sp.…”
Section: Pgpm Tolerance To High N Concentrationsmentioning
Background: Populations of plant growth-promoting microorganisms (PGPMs) inoculated in natural soil typically decline over time due unfavourable biotic and/or abiotic factor(s). Improving subsurface root density may enhance PGPM establishment due to high concentrations of organic nutrients released as root exudates. Placing subsurface root-attracting NH 4 + -fertilizer depots may form such zones of dense localized rooting ("rhizosphere hotspots") that can enhance PGPM survival. Nevertheless, required soil conditions that favour formation of rhizosphere hotspots are unknown. This study aimed to investigate: (1) background soil N min effect on NH 4 + -depot-zone root growth; (2) PGPM tolerance to high NH 4 + concentrations (± nitrification inhibitor, DMPP); (3) ability to solubilize sparingly soluble inorganic phosphates; (4) and establishment in a subsurface NH 4 + -depot.
Methods:We conducted a greenhouse rhizobox experiment using spring wheat (Triticum aestivum L.) to investigate the effect of background N min (0, 5, 20 and 60 mg N kg
Conclusion:These results show the first promising effects of combining fertilizer placement and application of P-solubilizing PGPMs on plant growth.
“…The antagonists form appressory structures and tightly coil around the full extent of the hypha penetrating and degrading it [47][48][49]. This mechanism has already been demonstrated by many researchers through interactions of T. harzianum, T. viride and T. asperellum with Rhizoctonia solani, Pythium spp., Fusarium oxysporum, F. solani, S. rolfsii, S. sclerotiorum, Botrytis cinerea, Phytophthora spp., Macrophomina phaseolina, and Alternaria solani [45,[47][48][49][50][51][52].…”
Section: In Vitro Antagonistic Activity To S Sclerotiorummentioning
Biological control agents are alternatives to chemical pesticides in the management of plant diseases. Currently, hundreds of bioproducts are commercially available in international market varying mainly in antagonistic microorganisms and formulation. We screened four Trichoderma-based products as to their efficacy in controlling Sclerotinia stem rot (SSR) under protected and field environments and their effect on soybean seeds' sanity and physiological qualities. We also tested application technologies through seed microbiolization and foliar spraying to deliver the microorganisms, and their compatibility with chemical fungicides. In vitro assays showed that all Trichoderma strains were antagonistic to S. sclerotiorum evidencing hyperparasitic activity. Moreover, the bioproducts reduced fungi incidence on soybean seeds, promoted faster seedling emergence and did not hamper seeds' vigor. Increases of 14 and 37% were registered for root length and shoot fresh weight over that of the untreated control indicating potential application of the bioproducts as soybean growth promoters. Thiophanate-methyl and procymidone were the most compatible, without drastically affecting spore germination or mycelium growth. Under field conditions, all Trichoderma strains reduced SSR incidence and increased soybean grain yield. Formulation interferes on bioproducts' viability and efficacy deserving special attention upon development.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.