In recent years,the prevalence of rice sheath blight caused by Rhizoctonia solani has significantly increased in Heilongjiang Province.Chemical control has become the primary control method.To cope with this,a novel m...In recent years,the prevalence of rice sheath blight caused by Rhizoctonia solani has significantly increased in Heilongjiang Province.Chemical control has become the primary control method.To cope with this,a novel mycelium growth rate method was employed to assess the toxicity of 13 fungicides,including a combination of 45%prochloraz and 125 g·mL^(-1)epoxiconazole,against R.solani.Additionally,the resistance of 99 R.solani strains to thifluzamide across various regions was also evaluated.The findings indicated that 75%trifloxystrobin-tebuconazole exhibited the most effective inhibitory effect,with an effective inhibitory medium concentration(EC50)value of 0.0101μg·mL^(-1).The EC50 values for 20%prothioconazole,125 g·mL^(-1)epoxiconazole,24%thifluzamide,and 50%hexaconazole were all less than 10μg·mL^(-1),indicating a better inhibitory effect on R.solani.The strongest synergistic effect was noted in the mixture of prochloraz and epoxiconazole at a 1:2 ratio,resulting in an EC50 value of 2.9917μg·mL^(-1),and a co-toxicity coefficient of 213.38.Among the 34 strains from Harbin City,the average EC50 value was 196.9341μg·mL^(-1)indicating the highest susceptiblility to thifluzamide.Conversely,15 strains from Shuangyashan City exhibited an average EC50 value of 364.7323μg·mL^(-1),reflecting the lowest sensitivity to thifluzamide.The sensitivity baseline EC50 value for R.solani was 253.8854μg·mL^(-1),with an overall resistance level between 0.1567 and 3.3292,indicating that the resistance level of R.solani in Heilongjiang Province remained low.Therefore,R.solani was still sensitive to thifluzamide in most areas of Heilongjiang Province,but there was a certain risk of resistance in Qitaihe City,which needed to be continuously monitored.At the same time,this study might provide a theoretical foundation for enhancing the prevention and management of the rice sheath blight.展开更多
分别基于7个烟草靶斑病菌株基因组中ITS-5.8S r DNA序列设计引物和探针;并对引物及探针特异性进行验证;建立检测体系并对接种烟草靶斑病菌的叶片和土壤中的烟草靶斑病菌进行检测。结果表明:所设计的引物及探针对R.solani AG-3具有特异性...分别基于7个烟草靶斑病菌株基因组中ITS-5.8S r DNA序列设计引物和探针;并对引物及探针特异性进行验证;建立检测体系并对接种烟草靶斑病菌的叶片和土壤中的烟草靶斑病菌进行检测。结果表明:所设计的引物及探针对R.solani AG-3具有特异性,检测体系可以检测出烟草叶片及土壤样品中的烟草靶斑病菌。接种烟草叶片的检测表明,接种后6h就可检测到强致病力菌株YC-9,12h后能检测到弱致病力菌株LF-2;获得了烟草靶斑病菌DNA质量的对数与添加菌丝量的对数之间的回归曲线方程,对不同月份土壤样品的测定结果表明烟草靶斑病菌在土壤中呈周年动态变化趋势。展开更多
The soil-borne pathogen Rhizoctonia solani Kühn (teleomorph, Thanatephorus cucumeris [A.B. Frank] Donk) is worldwide responsible for serious damage of many economically important agricultural and horticultural cr...The soil-borne pathogen Rhizoctonia solani Kühn (teleomorph, Thanatephorus cucumeris [A.B. Frank] Donk) is worldwide responsible for serious damage of many economically important agricultural and horticultural crops. Control of Rhizoctonia diseases is difficult because this pathogen survives for many years as sclerotia in soil or as mycelium in organic matter under numerous environmental conditions. Furthermore, the pathogen has an extremely wide host range. To date, no effective control strategies against Rhizoctonia diseases are available in either organic farming or horticulture. In integrated pest management systems (IPM), mainly fungicides are used as control method. However, the European Union has decided that 60% of the chemical pesticides that were allowed in 1996 should be banned from 2003. Hence, new strategies to control one of the most important soil-borne pathogen R. solani are urgently needed. It is well-documented that an environmentally friendly alternative to protect plants against soil borne pathogens is biological control. Our work is concentrated on the development of a fungal biological control agent (BCA) especially selected against diseases caused by R. solani.. Based on a combination of in vitro and in vivo assays 339 fungal plant-associated strains was evaluated against R. solani. The following characteristics were tested in vitro: antagonistic activity at 20 ℃ and 12 ℃, the ability to produce cell wall-degrading enzymes (chitinase, β-1,3-glucanase, protease), and influence on sclerotia germination. The ability of spore production was also of importance under consideration of formulation of possible candidates. As results of the note characteristics six isolates were selected. Taxonomical characterization using molecular methods like BOX-PCR and sequencing of the 18S rDNA resulted in genetically diverse Trichoderma isolates. The disease suppression effect of the six fungal isolates were tested against bottom rot on lettuce and black scurf on potato in pot experiments in climate chamber. The conditions were favourable for the disease development by R. solani on both crops. All six isolates were able to suppress the disease severity on lettuce and potato. According to their biocontrol effect under field conditions the most efficient isolate will be commercialised as BCA product.展开更多
基金Supported by the Green Plant Protection Project(213010801)the Heilongjiang Province Key Research and Development Plan Project(20232X02 B0502)the Natural Science Foundation of Heilongjiang Province(LH2022C022)。
文摘In recent years,the prevalence of rice sheath blight caused by Rhizoctonia solani has significantly increased in Heilongjiang Province.Chemical control has become the primary control method.To cope with this,a novel mycelium growth rate method was employed to assess the toxicity of 13 fungicides,including a combination of 45%prochloraz and 125 g·mL^(-1)epoxiconazole,against R.solani.Additionally,the resistance of 99 R.solani strains to thifluzamide across various regions was also evaluated.The findings indicated that 75%trifloxystrobin-tebuconazole exhibited the most effective inhibitory effect,with an effective inhibitory medium concentration(EC50)value of 0.0101μg·mL^(-1).The EC50 values for 20%prothioconazole,125 g·mL^(-1)epoxiconazole,24%thifluzamide,and 50%hexaconazole were all less than 10μg·mL^(-1),indicating a better inhibitory effect on R.solani.The strongest synergistic effect was noted in the mixture of prochloraz and epoxiconazole at a 1:2 ratio,resulting in an EC50 value of 2.9917μg·mL^(-1),and a co-toxicity coefficient of 213.38.Among the 34 strains from Harbin City,the average EC50 value was 196.9341μg·mL^(-1)indicating the highest susceptiblility to thifluzamide.Conversely,15 strains from Shuangyashan City exhibited an average EC50 value of 364.7323μg·mL^(-1),reflecting the lowest sensitivity to thifluzamide.The sensitivity baseline EC50 value for R.solani was 253.8854μg·mL^(-1),with an overall resistance level between 0.1567 and 3.3292,indicating that the resistance level of R.solani in Heilongjiang Province remained low.Therefore,R.solani was still sensitive to thifluzamide in most areas of Heilongjiang Province,but there was a certain risk of resistance in Qitaihe City,which needed to be continuously monitored.At the same time,this study might provide a theoretical foundation for enhancing the prevention and management of the rice sheath blight.
文摘分别基于7个烟草靶斑病菌株基因组中ITS-5.8S r DNA序列设计引物和探针;并对引物及探针特异性进行验证;建立检测体系并对接种烟草靶斑病菌的叶片和土壤中的烟草靶斑病菌进行检测。结果表明:所设计的引物及探针对R.solani AG-3具有特异性,检测体系可以检测出烟草叶片及土壤样品中的烟草靶斑病菌。接种烟草叶片的检测表明,接种后6h就可检测到强致病力菌株YC-9,12h后能检测到弱致病力菌株LF-2;获得了烟草靶斑病菌DNA质量的对数与添加菌丝量的对数之间的回归曲线方程,对不同月份土壤样品的测定结果表明烟草靶斑病菌在土壤中呈周年动态变化趋势。
文摘The soil-borne pathogen Rhizoctonia solani Kühn (teleomorph, Thanatephorus cucumeris [A.B. Frank] Donk) is worldwide responsible for serious damage of many economically important agricultural and horticultural crops. Control of Rhizoctonia diseases is difficult because this pathogen survives for many years as sclerotia in soil or as mycelium in organic matter under numerous environmental conditions. Furthermore, the pathogen has an extremely wide host range. To date, no effective control strategies against Rhizoctonia diseases are available in either organic farming or horticulture. In integrated pest management systems (IPM), mainly fungicides are used as control method. However, the European Union has decided that 60% of the chemical pesticides that were allowed in 1996 should be banned from 2003. Hence, new strategies to control one of the most important soil-borne pathogen R. solani are urgently needed. It is well-documented that an environmentally friendly alternative to protect plants against soil borne pathogens is biological control. Our work is concentrated on the development of a fungal biological control agent (BCA) especially selected against diseases caused by R. solani.. Based on a combination of in vitro and in vivo assays 339 fungal plant-associated strains was evaluated against R. solani. The following characteristics were tested in vitro: antagonistic activity at 20 ℃ and 12 ℃, the ability to produce cell wall-degrading enzymes (chitinase, β-1,3-glucanase, protease), and influence on sclerotia germination. The ability of spore production was also of importance under consideration of formulation of possible candidates. As results of the note characteristics six isolates were selected. Taxonomical characterization using molecular methods like BOX-PCR and sequencing of the 18S rDNA resulted in genetically diverse Trichoderma isolates. The disease suppression effect of the six fungal isolates were tested against bottom rot on lettuce and black scurf on potato in pot experiments in climate chamber. The conditions were favourable for the disease development by R. solani on both crops. All six isolates were able to suppress the disease severity on lettuce and potato. According to their biocontrol effect under field conditions the most efficient isolate will be commercialised as BCA product.
