A new endophytic antagonistic fungus, Chaetomium spirale ND35 from Populus tomentosa, was reported. The bio-control trials of C. spirale ND35 against the Valsa Canker of apple were preliminarily investigated. The resu...A new endophytic antagonistic fungus, Chaetomium spirale ND35 from Populus tomentosa, was reported. The bio-control trials of C. spirale ND35 against the Valsa Canker of apple were preliminarily investigated. The results of dual culture on PDA plate showed that C. spirale ND35 was capable of strong antagonism against Valsa ceratosperma, and for inhibiting the mycelial growth of V. ceratosperma,.the crude extract of liquid culture of corn steep powder broth was more effective than that one of malt extract broth (MEB). The results of bio-control in greenhouse and field indicated that the disease incidence of apple tree treated with C. spirale ND35 was lower significantly than that treated by other methods. The re-isolation experiment suggested that C. spirale ND35 could colonize in stems and branches of apple trees successfully, and the ND35 colonization rate of the treatment with solid wheat bran culture was higher than that of corn steep powder broth, but the field experiment result the control effect of liquid culture of C. spirale ND35 was better than that of solid culture.展开更多
Mycotoxins and their derivatives since their discoveries and until the present time are behind unspecified economic and medical damages.Aflatoxins are classified according to their physical–chemical and toxicological...Mycotoxins and their derivatives since their discoveries and until the present time are behind unspecified economic and medical damages.Aflatoxins are classified according to their physical–chemical and toxicological characters in the most dangerous row of the mycotoxins.These aflatoxins are in part responsible,of irreversible medical disasters that are not easily manageable such as cancer of the liver and kidneys,and in the other part,of losses in the stored cereal products.Based on these crucial findings,monitoring of this toxin became imperative in post-harvest food products,during storage,during transformation chain and even during the long phases of conservation.Vigilance of this toxin is delivered by detection methods using very advanced technologies to respond in the shortest possible times.In addition,the knowledge of factors supporting the biosynthesis of aflatoxins such as the temperature,moisture content,concentration of nitrogen and carbon,and the molecules responsible for the genetic control of the synthesis will be reflected later in the choice of bio-control techniques.This control is currently based on new strategies using the bioactives substances of the plants,the lactic bacteria and some strains of actinomycetes that have good inhibiting activity against aflatoxins with fewer side effects on Man.On the other hand,this brief review summarizes the results of new studies demonstrating the toxicity of the toxin,new detection methods and bio-control.展开更多
In recent years, researchers tended to bring new alternative to biological protective systems used in conservation of food and production of safe food. Use of bacteriophage against to pathogen bacteria in food was the...In recent years, researchers tended to bring new alternative to biological protective systems used in conservation of food and production of safe food. Use of bacteriophage against to pathogen bacteria in food was the most hopeful system in these methods about bio-control. Controls of bacteriophage for each pathogen species and subspecies and determination of phage-host originality are important because efficient bio-control was achieved. Researches concentrated on some food-borne pathogen bacteria such as E. coli O157：H7, Campylobacter, Salmonella and Listeria. In a consequence of these studies made as in vitro and in vivo, first commercial production of phage which will be used in foods was made in Netherlands. Also, it has been informed that use of phage is cost-efficient alternative as compared with other preservatives. This review, discussed application of bacteriophages as bio-control agents in food and advantages and disadvantages about uses of bacteriophages by taking into account antimicrobial characteristics of them.展开更多
Field experiments were conducted at two key locations in two successive seasons in Nigeria to determine the role of habitat manipulation in the bio-control of African rice gall midge, Orseolia oryzivora using Platygas...Field experiments were conducted at two key locations in two successive seasons in Nigeria to determine the role of habitat manipulation in the bio-control of African rice gall midge, Orseolia oryzivora using Platygaster diplosisae an endoparasitoid of the midge. The habitat manipulation strategy tested in the study was to plant seedlings ofPaspalum scrobiculatum on one meter strip of land at the border of each rice plot early in the cropping season to conserve P. diplosisae in its alternative host, Orseolia bonzii that infest P. scrobiculatum. The Paspalum seedlings were allowed to be fully established, infested naturally by 0. bonzii and parasitized by P. diplosisae before transplanting rice varieties in each plot. The control plots were planted with only rice seedlings leaving the border empty without any Paspalum. Rice plots with Paspalum at the edge had much lower levels of O. oryzivora infestation than the control plots. The percentage number of gall midge parasitized by P. diplosisae showed that rice plots with Paspalum at the edge had more parasitized galls than the control plots without Paspalum. The role of the Paspalum border was substantiated with the negative correlation results recorded with the infestation indicating significant decrease in the percentage tiller infestation as the percentage parasitism increased. That resulted in higher grain yield in the plots surrounded with Paspalum treatment than in the control. The present study therefore demonstrated that management of P. scrobiculatum on a strip of land around the edge of rice crops could significantly increase parasitoid carry-over into the crop.展开更多
为中药材根腐病的生物防治提供有效的生防种质资源,本文从1万多株细菌中通过平板拮抗法筛选获得3株对镰刀菌抑菌活性较强的根际细菌LHJS2-2、LHQS2-5和YHQS2-7,对尖孢镰刀菌F.oxysporum295、腐皮镰刀菌F.solaniN18和轮枝镰刀菌F.vertici...为中药材根腐病的生物防治提供有效的生防种质资源,本文从1万多株细菌中通过平板拮抗法筛选获得3株对镰刀菌抑菌活性较强的根际细菌LHJS2-2、LHQS2-5和YHQS2-7,对尖孢镰刀菌F.oxysporum295、腐皮镰刀菌F.solaniN18和轮枝镰刀菌F.verticillium173的抑菌带为12~17mm,对串珠镰刀菌F.moniliforme N19的抑菌带是3~5 mm。经形态观察、生理生化试验及16S r DNA鉴定结果表明,菌株LHJS2-2为短小芽胞杆菌B.pumilus,菌株LHQS2-5为贝莱斯芽胞杆菌B.velezensis,菌株YHQS2-7为深褐芽胞杆菌B.atrophaeus。盆栽试验结果表明,菌株LHJS2-2、LHQS2-5和YHQS2-7对黄芪根腐病的预防效果分别是88.07%、85.66%和76.73%,显著促进黄芪、黄芩、银柴胡幼苗株高、根长、地上部生物量和地下部生物量。田间试验结果表明,菌株LHJS2-2、LHQS2-5和YHQS2-7对黄芪根腐病的防治效果分别为41.37%、40.13%和41.95%,对党参根腐病的田间预防效果分别达到87.06%、95.03%和87.06%。菌株LHJS2-2、LHQS2-5和YHQS2-7对中药材根腐病的生物防治具有重要的前景。展开更多
Aim: This study was carried out in order to evaluate the potential of bacteriophages in controlling tomato bacterial wilt disease caused by Ralstonia solanacearum. Study design: A purposive sampling technique was used...Aim: This study was carried out in order to evaluate the potential of bacteriophages in controlling tomato bacterial wilt disease caused by Ralstonia solanacearum. Study design: A purposive sampling technique was used to collect samples from bacterial wilt hot spot tomato growing areas in Kenya. Place and duration of study: The research work was done at Jomo Kenyatta University of Agriculture and Technology, between June 2020 and July 2021. Methodology: Thirty diseased plants and corresponding soil were collected from five counties, Nyeri, Kajiado, Nyandarua, Kiambu and Taita Taveta. Bacteria were isolated and characterized, and then used as hosts to propagate the phages. Tests done were gram stain, oxidation test, potassium hydroxide solubility test, H2S production test catalase test, NaCl test and sugar fermentation test. Molecular analysis and phenotyping were also done in order to identify the bacteria. The bacteriophages were then isolated through a double overlay method using R. solanacearum as the host. They were characterized and assayed in a greenhouse setting to determine their effectiveness in controlling bacterial wilt. Results: Six host bacteria were isolated and all belonged to biovar II. Four phages were observed based on morphology. Upon characterization the phages were stable at 30˚C, PH range between 6 - 7 and tolerance of more than an hour under UV light. In the greenhouse experiment, treatment of plants with bacteriophage prevented wilting after subsequent inoculation with the pathogen. A bacteriophage mix of SN1 and WT1 were used for efficacy tests due to their efficiency in plating and infection. Phage SN1 and WT1 exhibited high lytic activity and relatively high thermotolerance and acid tolerance, thereby showing great potential in the biocontrol of bacterial wilt infection across a variety of conditions. Conclusion: The results obtained in this research show that bacteriophages offer potential for the biocontrol of bacterial wilt.展开更多
基金This research was supported by National Natural Science Foundation of China (Grant No. 30100143)
文摘A new endophytic antagonistic fungus, Chaetomium spirale ND35 from Populus tomentosa, was reported. The bio-control trials of C. spirale ND35 against the Valsa Canker of apple were preliminarily investigated. The results of dual culture on PDA plate showed that C. spirale ND35 was capable of strong antagonism against Valsa ceratosperma, and for inhibiting the mycelial growth of V. ceratosperma,.the crude extract of liquid culture of corn steep powder broth was more effective than that one of malt extract broth (MEB). The results of bio-control in greenhouse and field indicated that the disease incidence of apple tree treated with C. spirale ND35 was lower significantly than that treated by other methods. The re-isolation experiment suggested that C. spirale ND35 could colonize in stems and branches of apple trees successfully, and the ND35 colonization rate of the treatment with solid wheat bran culture was higher than that of corn steep powder broth, but the field experiment result the control effect of liquid culture of C. spirale ND35 was better than that of solid culture.
文摘Mycotoxins and their derivatives since their discoveries and until the present time are behind unspecified economic and medical damages.Aflatoxins are classified according to their physical–chemical and toxicological characters in the most dangerous row of the mycotoxins.These aflatoxins are in part responsible,of irreversible medical disasters that are not easily manageable such as cancer of the liver and kidneys,and in the other part,of losses in the stored cereal products.Based on these crucial findings,monitoring of this toxin became imperative in post-harvest food products,during storage,during transformation chain and even during the long phases of conservation.Vigilance of this toxin is delivered by detection methods using very advanced technologies to respond in the shortest possible times.In addition,the knowledge of factors supporting the biosynthesis of aflatoxins such as the temperature,moisture content,concentration of nitrogen and carbon,and the molecules responsible for the genetic control of the synthesis will be reflected later in the choice of bio-control techniques.This control is currently based on new strategies using the bioactives substances of the plants,the lactic bacteria and some strains of actinomycetes that have good inhibiting activity against aflatoxins with fewer side effects on Man.On the other hand,this brief review summarizes the results of new studies demonstrating the toxicity of the toxin,new detection methods and bio-control.
文摘In recent years, researchers tended to bring new alternative to biological protective systems used in conservation of food and production of safe food. Use of bacteriophage against to pathogen bacteria in food was the most hopeful system in these methods about bio-control. Controls of bacteriophage for each pathogen species and subspecies and determination of phage-host originality are important because efficient bio-control was achieved. Researches concentrated on some food-borne pathogen bacteria such as E. coli O157：H7, Campylobacter, Salmonella and Listeria. In a consequence of these studies made as in vitro and in vivo, first commercial production of phage which will be used in foods was made in Netherlands. Also, it has been informed that use of phage is cost-efficient alternative as compared with other preservatives. This review, discussed application of bacteriophages as bio-control agents in food and advantages and disadvantages about uses of bacteriophages by taking into account antimicrobial characteristics of them.
文摘Field experiments were conducted at two key locations in two successive seasons in Nigeria to determine the role of habitat manipulation in the bio-control of African rice gall midge, Orseolia oryzivora using Platygaster diplosisae an endoparasitoid of the midge. The habitat manipulation strategy tested in the study was to plant seedlings ofPaspalum scrobiculatum on one meter strip of land at the border of each rice plot early in the cropping season to conserve P. diplosisae in its alternative host, Orseolia bonzii that infest P. scrobiculatum. The Paspalum seedlings were allowed to be fully established, infested naturally by 0. bonzii and parasitized by P. diplosisae before transplanting rice varieties in each plot. The control plots were planted with only rice seedlings leaving the border empty without any Paspalum. Rice plots with Paspalum at the edge had much lower levels of O. oryzivora infestation than the control plots. The percentage number of gall midge parasitized by P. diplosisae showed that rice plots with Paspalum at the edge had more parasitized galls than the control plots without Paspalum. The role of the Paspalum border was substantiated with the negative correlation results recorded with the infestation indicating significant decrease in the percentage tiller infestation as the percentage parasitism increased. That resulted in higher grain yield in the plots surrounded with Paspalum treatment than in the control. The present study therefore demonstrated that management of P. scrobiculatum on a strip of land around the edge of rice crops could significantly increase parasitoid carry-over into the crop.
文摘为中药材根腐病的生物防治提供有效的生防种质资源,本文从1万多株细菌中通过平板拮抗法筛选获得3株对镰刀菌抑菌活性较强的根际细菌LHJS2-2、LHQS2-5和YHQS2-7,对尖孢镰刀菌F.oxysporum295、腐皮镰刀菌F.solaniN18和轮枝镰刀菌F.verticillium173的抑菌带为12~17mm,对串珠镰刀菌F.moniliforme N19的抑菌带是3~5 mm。经形态观察、生理生化试验及16S r DNA鉴定结果表明,菌株LHJS2-2为短小芽胞杆菌B.pumilus,菌株LHQS2-5为贝莱斯芽胞杆菌B.velezensis,菌株YHQS2-7为深褐芽胞杆菌B.atrophaeus。盆栽试验结果表明,菌株LHJS2-2、LHQS2-5和YHQS2-7对黄芪根腐病的预防效果分别是88.07%、85.66%和76.73%,显著促进黄芪、黄芩、银柴胡幼苗株高、根长、地上部生物量和地下部生物量。田间试验结果表明,菌株LHJS2-2、LHQS2-5和YHQS2-7对黄芪根腐病的防治效果分别为41.37%、40.13%和41.95%,对党参根腐病的田间预防效果分别达到87.06%、95.03%和87.06%。菌株LHJS2-2、LHQS2-5和YHQS2-7对中药材根腐病的生物防治具有重要的前景。
文摘Aim: This study was carried out in order to evaluate the potential of bacteriophages in controlling tomato bacterial wilt disease caused by Ralstonia solanacearum. Study design: A purposive sampling technique was used to collect samples from bacterial wilt hot spot tomato growing areas in Kenya. Place and duration of study: The research work was done at Jomo Kenyatta University of Agriculture and Technology, between June 2020 and July 2021. Methodology: Thirty diseased plants and corresponding soil were collected from five counties, Nyeri, Kajiado, Nyandarua, Kiambu and Taita Taveta. Bacteria were isolated and characterized, and then used as hosts to propagate the phages. Tests done were gram stain, oxidation test, potassium hydroxide solubility test, H2S production test catalase test, NaCl test and sugar fermentation test. Molecular analysis and phenotyping were also done in order to identify the bacteria. The bacteriophages were then isolated through a double overlay method using R. solanacearum as the host. They were characterized and assayed in a greenhouse setting to determine their effectiveness in controlling bacterial wilt. Results: Six host bacteria were isolated and all belonged to biovar II. Four phages were observed based on morphology. Upon characterization the phages were stable at 30˚C, PH range between 6 - 7 and tolerance of more than an hour under UV light. In the greenhouse experiment, treatment of plants with bacteriophage prevented wilting after subsequent inoculation with the pathogen. A bacteriophage mix of SN1 and WT1 were used for efficacy tests due to their efficiency in plating and infection. Phage SN1 and WT1 exhibited high lytic activity and relatively high thermotolerance and acid tolerance, thereby showing great potential in the biocontrol of bacterial wilt infection across a variety of conditions. Conclusion: The results obtained in this research show that bacteriophages offer potential for the biocontrol of bacterial wilt.
