This study highlights the regulatory potential antibacterial and antiradical of Origanum elongatum essential oil(EO),an endemic medicinal plant of Morocco used for its various properties.The chemical composition of th...This study highlights the regulatory potential antibacterial and antiradical of Origanum elongatum essential oil(EO),an endemic medicinal plant of Morocco used for its various properties.The chemical composition of the EO was characterized using gas chromatography-mass spectrometry(GC-MS).The antibacterial activity against different agricultural phytopathogens was determined by disc diffusion and microatmosphere methods,as well as by the determination of minimum inhibitory concentrations(MIC)and minimum bactericidal concentration(MBC),while the antioxidant activity was evaluated by DPPH and FRAP assays.To complement the experimental analyses,a molecular docking approach was used to predict and elucidate the mechanisms of action of the identified bioactive com-pounds,both for their antioxidant and antibacterial properties.The GC-MS analysis revealed a chemical composition dominated by the major compounds:p-cymene-2-ol(25.31%),thymol(23.88%),andγ-terpinene(19.26%).Furthermore,antibacterial analyses performed using different methodological approaches(disc diffusion,microatmosphere,MIC,and MBC)showed significant inhibitory activity against all phytopathogens tested.Moreover,O.elongatum EO exhibited interesting antioxidant ability with an IC_(50) value of 168.251.14μg/mL for DPPH assay and EC_(50) value±of 164.221.04μg/mL for FRAP assay.Furthermore,in silico molecular docking demonstrated further insights into±the interactions between the oil’s active components and bacterial targets,supporting its mode of action.This in-depth characterization highlights the potential of O.elongatum EO as a natural alternative for the biocontrol of plant pathogens.It opens new perspectives for developing natural solutions to protect crops against plant diseases.展开更多
This paper reviews the potential for using insect pathogens to control the Colorado potato beetle,Leptinotarsa decemlineata,and summarizes results from nearly 10 years of research by USDA-ARS-PPRU scientists aimed at ...This paper reviews the potential for using insect pathogens to control the Colorado potato beetle,Leptinotarsa decemlineata,and summarizes results from nearly 10 years of research by USDA-ARS-PPRU scientists aimed at developing methods and strategies for integrated use of Bacillus thuringiensis and Beauveria bassiana for biologically-based management of potato beetles in the northeastern USA.The described studies have resulted in 1)design of a tractor-mounted hydraulic spray system that improved targeting and consequent efficacy of microbial control agents,2)discovery of synergism between the bacterial pathogen Bacillus thuringiensis(Bt)and the fungal pathogen Beauveria bassiana(Bb),3)findings that substantial mortality of beetle larvae treated with B.bassiana during foliar spray programs did not occur until after they entered the soil to pupate,and 4)observations that spray applications made in the evening(at sunset)were significantly,but not substantially,more effective than applications made during the morning hours.These findings have led to development of a bio-based pest management system based on three spray applications made in the following order at 3-5-day intervals:Bt alone,Bt and Bb mixed,and Bb alone.This spray program,with the applications initiated at 50% egg hatch,is intended to control the actively feeding larval stages(providing protection from defoliation)and reduce survivorship to the adult stage(providing long-term control by reducing populations of overwintering adults).In the initial test of the integrated management system,beetle control and potato yields were statistically equivalent to those in plots in which the beetles were controlled with chemical insecticides.Demonstration of the effectiveness of this program will continue over the next 2-3 field seasons.展开更多
文摘This study highlights the regulatory potential antibacterial and antiradical of Origanum elongatum essential oil(EO),an endemic medicinal plant of Morocco used for its various properties.The chemical composition of the EO was characterized using gas chromatography-mass spectrometry(GC-MS).The antibacterial activity against different agricultural phytopathogens was determined by disc diffusion and microatmosphere methods,as well as by the determination of minimum inhibitory concentrations(MIC)and minimum bactericidal concentration(MBC),while the antioxidant activity was evaluated by DPPH and FRAP assays.To complement the experimental analyses,a molecular docking approach was used to predict and elucidate the mechanisms of action of the identified bioactive com-pounds,both for their antioxidant and antibacterial properties.The GC-MS analysis revealed a chemical composition dominated by the major compounds:p-cymene-2-ol(25.31%),thymol(23.88%),andγ-terpinene(19.26%).Furthermore,antibacterial analyses performed using different methodological approaches(disc diffusion,microatmosphere,MIC,and MBC)showed significant inhibitory activity against all phytopathogens tested.Moreover,O.elongatum EO exhibited interesting antioxidant ability with an IC_(50) value of 168.251.14μg/mL for DPPH assay and EC_(50) value±of 164.221.04μg/mL for FRAP assay.Furthermore,in silico molecular docking demonstrated further insights into±the interactions between the oil’s active components and bacterial targets,supporting its mode of action.This in-depth characterization highlights the potential of O.elongatum EO as a natural alternative for the biocontrol of plant pathogens.It opens new perspectives for developing natural solutions to protect crops against plant diseases.
文摘This paper reviews the potential for using insect pathogens to control the Colorado potato beetle,Leptinotarsa decemlineata,and summarizes results from nearly 10 years of research by USDA-ARS-PPRU scientists aimed at developing methods and strategies for integrated use of Bacillus thuringiensis and Beauveria bassiana for biologically-based management of potato beetles in the northeastern USA.The described studies have resulted in 1)design of a tractor-mounted hydraulic spray system that improved targeting and consequent efficacy of microbial control agents,2)discovery of synergism between the bacterial pathogen Bacillus thuringiensis(Bt)and the fungal pathogen Beauveria bassiana(Bb),3)findings that substantial mortality of beetle larvae treated with B.bassiana during foliar spray programs did not occur until after they entered the soil to pupate,and 4)observations that spray applications made in the evening(at sunset)were significantly,but not substantially,more effective than applications made during the morning hours.These findings have led to development of a bio-based pest management system based on three spray applications made in the following order at 3-5-day intervals:Bt alone,Bt and Bb mixed,and Bb alone.This spray program,with the applications initiated at 50% egg hatch,is intended to control the actively feeding larval stages(providing protection from defoliation)and reduce survivorship to the adult stage(providing long-term control by reducing populations of overwintering adults).In the initial test of the integrated management system,beetle control and potato yields were statistically equivalent to those in plots in which the beetles were controlled with chemical insecticides.Demonstration of the effectiveness of this program will continue over the next 2-3 field seasons.
