RESUMO
Fusarium head blight (FHB) caused by Fusarium graminearum species complex is a devastating disease that causes extensive yield and quality losses to wheat around the world. Fungicide application and breeding for resistance are among the most important tools to counteract FHB. Biological control is an additional tool that can be used as part of an integrated management of FHB. Bacillus velezensisRC 218, Brevibacillus sp. RC 263 and Streptomyces sp. RC 87B were selected by their potential to control FHB and deoxynivalenol production. The aim of this work was to test the tolerance of these biocontrol agents to triazole-based fungicides such as prothioconazole, tebuconazole and metconazole. Bacterial growth was evaluated in Petri dishes using the spread plating technique containing the different fungicides. Bacillus velezensisRC 218 and Streptomyces sp. RC 87B showed better tolerance to fungicides than Brevibacillus sp. RC 263. Complete growth inhibition was observed at concentrations of 20 µg ml-1 for metconazole, 40 µg ml-1 for tebuconazole and 80 µg ml-1 for prothioconazole. The results obtained indicate the possibility of using these biocontrol agents in combination with fungicides as part of an integrated management to control FHB of wheat. SIGNIFICANCE AND IMPACT OF THE STUDY: This study evaluates the possibility to use biocontrol agents (Bacillus velezensisRC 218, Brevibacillus sp. RC 263 and Streptomyces sp. RC 87B) in combination with triazole-based fungicides to control Fusarium head blight in wheat. The evaluation of biocontrol agents' growth under in vitro conditions was carried out in Petri dishes containing either prothioconazole, tebuconazole or metconazole. Viability studies demonstrated that B. velezensisRC 218 and Streptomyces sp. RC 87B were more tolerant to the fungicides evaluated. Results obtained reflect the possibility to use fungicides at low doses combined with biocontrol agents.
Assuntos
Bacillus/efeitos dos fármacos , Agentes de Controle Biológico/metabolismo , Brevibacillus/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Streptomyces/efeitos dos fármacos , Triazóis/farmacologia , Antibiose/fisiologia , Argentina , Bacillus/crescimento & desenvolvimento , Bacillus/metabolismo , Brevibacillus/crescimento & desenvolvimento , Brevibacillus/metabolismo , Fusarium/efeitos dos fármacos , Doenças das Plantas/microbiologia , Streptomyces/crescimento & desenvolvimento , Streptomyces/metabolismo , Tricotecenos/biossíntese , Triticum/microbiologiaRESUMO
A bacterial strain (PAP04) isolated from cattle farm soil was shown to produce an extracellular, solvent-stable protease. Sequence analysis using 16S rRNA showed that this strain was highly homologous (99%) to Brevibacillus laterosporus. Growth conditions that optimize protease production in this strain were determined as maltose (carbon source), skim milk (nitrogen source), pH 7.0, 40°C temperature, and 48 h incubation. Overall, conditions were optimized to yield a 5.91-fold higher production of protease compared to standard conditions. Furthermore, the stability of the enzyme in organic solvents was assessed by incubation for 2 weeks in solutions containing 50% concentration of various organic solvents. The enzyme retained activity in all tested solvents except ethanol; however, the protease activity was stimulated in benzene (74%) followed by acetone (63%) and chloroform (54.8%). In addition, the plate assay and zymography results also confirmed the stability of the PAP04 protease in various organic solvents. The organic solvent stability of this protease at high (50%) concentrations of solvents makes it an alternative catalyst for peptide synthesis in non-aqueous media.
Assuntos
Proteínas de Bactérias/biossíntese , Brevibacillus/metabolismo , Compostos Orgânicos/metabolismo , Peptídeo Hidrolases/biossíntese , Animais , Proteínas de Bactérias/química , Brevibacillus/isolamento & purificação , Bovinos , Meios de Cultura , Eletroforese em Gel de Poliacrilamida , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Peptídeo Hidrolases/química , Microbiologia do Solo , Solventes , Temperatura , Fatores de TempoRESUMO
A bacterial strain (PAP04) isolated from cattle farm soil was shown to produce an extracellular, solvent-stable protease. Sequence analysis using 16S rRNA showed that this strain was highly homologous (99%) to Brevibacillus laterosporus. Growth conditions that optimize protease production in this strain were determined as maltose (carbon source), skim milk (nitrogen source), pH 7.0, 40°C temperature, and 48 h incubation. Overall, conditions were optimized to yield a 5.91-fold higher production of protease compared to standard conditions. Furthermore, the stability of the enzyme in organic solvents was assessed by incubation for 2 weeks in solutions containing 50% concentration of various organic solvents. The enzyme retained activity in all tested solvents except ethanol; however, the protease activity was stimulated in benzene (74%) followed by acetone (63%) and chloroform (54.8%). In addition, the plate assay and zymography results also confirmed the stability of the PAP04 protease in various organic solvents. The organic solvent stability of this protease at high (50%) concentrations of solvents makes it an alternative catalyst for peptide synthesis in non-aqueous media.
Assuntos
Animais , Compostos Orgânicos/metabolismo , Peptídeo Hidrolases/biossíntese , Proteínas de Bactérias/biossíntese , Brevibacillus/metabolismo , Peptídeo Hidrolases/química , Microbiologia do Solo , Solventes , Temperatura , Fatores de Tempo , Proteínas de Bactérias/química , Estabilidade Enzimática , Bovinos , Meios de Cultura , Eletroforese em Gel de Poliacrilamida , Brevibacillus/isolamento & purificação , Concentração de Íons de HidrogênioRESUMO
In the present study, a bacterium isolated from Marcha- a herbal cake used as traditional starter culture to ferment local wine in North East India, was evaluated for bacteriocin like inhibitory substance production and was tested against six food borne/spoilage causing pathogens viz. Listeria monocytogenes MTCC 839, Bacillus subtilis MTCC 121, Clostridium perfringens MTCC 450, Staphylococcus aureus, Lactobacillus plantarum and Leuconostoc mesenteroides MTCC 107 by using bit/disc method followed by well diffusion method. The bacterial isolate was identified as Brevibacillus borstelensis on the basis of phenotypic, biochemical and molecular characteristics using 16Sr RNA gene technique. Bacteriocin like inhibitory substance produced by Brevibacillus borstelensis AG1 was purified by gel exclusion chromatography. The molecular mass of the Brevibacillus borstelensis AG1 was found to be 12 kDa. Purified bacteriocin like inhibitory substance of Brevibacillus borstelensis was further characterized by studying the effect of temperature, pH, proteolytic enzyme and stability. Bacteriocin like inhibitory substance was found to be thermostable upto 100 °C, active at neutral pH, sensitive to trypsin, and partially stable till third week of storage thus showing a bright prospective to be used as a potential food biopreservative.
Assuntos
Bacteriocinas/isolamento & purificação , Bacteriocinas/farmacologia , Brevibacillus/isolamento & purificação , Brevibacillus/metabolismo , Bactérias Gram-Positivas/efeitos dos fármacos , Bacteriocinas/química , Cromatografia em Gel , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Microbiologia de Alimentos , Índia , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Peso Molecular , Filogenia , Estabilidade Proteica/efeitos da radiação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , TemperaturaRESUMO
In the present study, a bacterium isolated from Marcha- a herbal cake used as traditional starter culture to ferment local wine in North East India, was evaluated for bacteriocin like inhibitory substance production and was tested against six food borne/spoilage causing pathogens viz. Listeria monocytogenes MTCC 839, Bacillus subtilis MTCC 121, Clostridium perfringens MTCC 450, Staphylococcus aureus, Lactobacillus plantarum and Leuconostoc mesenteroides MTCC 107 by using bit/disc method followed by well diffusion method. The bacterial isolate was identified as Brevibacillus borstelensis on the basis of phenotypic, biochemical and molecular characteristics using 16Sr RNA gene technique. Bacteriocin like inhibitory substance produced by Brevibacillus borstelensis AG1 was purified by gel exclusion chromatography. The molecular mass of the Brevibacillus borstelensis AG1 was found to be 12 kDa. Purified bacteriocin like inhibitory substance of Brevibacillus borstelensis was further characterized by studying the effect of temperature, pH, proteolytic enzyme and stability. Bacteriocin like inhibitory substance was found to be thermostable upto 100 °C, active at neutral pH, sensitive to trypsin, and partially stable till third week of storage thus showing a bright prospective to be used as a potential food biopreservative.
Assuntos
Bacteriocinas/isolamento & purificação , Bacteriocinas/farmacologia , Brevibacillus/isolamento & purificação , Brevibacillus/metabolismo , Bactérias Gram-Positivas/efeitos dos fármacos , Bacteriocinas/química , Cromatografia em Gel , Análise por Conglomerados , DNA Bacteriano/química , DNA Ribossômico/química , Microbiologia de Alimentos , ÍndiaRESUMO
In the present study, a bacterium isolated from Marcha- a herbal cake used as traditional starter culture to ferment local wine in North East India, was evaluated for bacteriocin like inhibitory substance production and was tested against six food borne/spoilage causing pathogens viz. Listeria monocytogenes MTCC 839, Bacillus subtilis MTCC 121, Clostridium perfringens MTCC 450, Staphylococcus aureus, Lactobacillus plantarum and Leuconostoc mesenteroides MTCC 107 by using bit/disc method followed by well diffusion method. The bacterial isolate was identified as Brevibacillus borstelensis on the basis of phenotypic, biochemical and molecular characteristics using 16Sr RNA gene technique. Bacteriocin like inhibitory substance produced by Brevibacillus borstelensis AG1 was purified by gel exclusion chromatography. The molecular mass of the Brevibacillus borstelensis AG1 was found to be 12 kDa. Purified bacteriocin like inhibitory substance of Brevibacillus borstelensis was further characterized by studying the effect of temperature, pH, proteolytic enzyme and stability. Bacteriocin like inhibitory substance was found to be thermostable upto 100 °C, active at neutral pH, sensitive to trypsin, and partially stable till third week of storage thus showing a bright prospective to be used as a potential food biopreservative.