Pyropia yezoensis(formerly Porphyra yezoensis)is an economically important red alga that is cultured extensively in China.The red rot disease occurs commonly during Pyropia cultivation,causing serious economic losses....Pyropia yezoensis(formerly Porphyra yezoensis)is an economically important red alga that is cultured extensively in China.The red rot disease occurs commonly during Pyropia cultivation,causing serious economic losses.An incidence of red rot disease was found in a P.yezoensis farm from mid-November to mid-December 2015 at Lianyungang,Jiangsu Province,China.Histopathological examination revealed that the naturally infected thalli were infected apparently by a pathogen,leading to red rot symptoms.The causative agent was isolated and identified as the oomycete Pythium chondricola by morphological analysis and sequence analysis of the internal transcribed spacer and cytochrome oxidase subunit 1(cox 1).In artifi cial infection experiments on the P.yezoensis blades,the P.chondricola isolate was able to cause the same characteristic histopathology seen in natural infections.P.chondricola grew well at a wide range of temperatures in the range 8-31℃,salinities at 0-45 and pH 5-9.In an orthogonal test used to determine the effects of environmental factors(temperature,salinity,and zoospore concentration)on infection,the data revealed that temperature was the most important factor to affect red rot disease development,with the optimal conditions for disease expansion being 20℃,35 salinity,and a zoospore concentration of 10^6 zoospores/mL.The results obtained from the present study prompted us to set up a comprehensive epidemiological study on Pyropia,which will provide support to maintain the healthy development of the Pyropia industry in China.展开更多
Three fungicide formulations, namely M1, M2 and M3, were prepared from sodium bicarbonate, citronella essential oil and sunflower slurry. The stability of M1, M2 and M3 formulations was determined based on pH, tempera...Three fungicide formulations, namely M1, M2 and M3, were prepared from sodium bicarbonate, citronella essential oil and sunflower slurry. The stability of M1, M2 and M3 formulations was determined based on pH, temperature, order of incorporation of the inputs and storage time. The most stable formulations were used for antagonistic tests on Pythium myriotylum. The Minimum Inhibitory Concentration (MIC) was used for the greenhouse tests and the mode of action was determined in vitro. The study showed that the order of incorporation of the inputs “Essential Oil-Tween 80-Bicarbonate-Slurry” (EO-T80-B-S) promotes stability. M1 and M2 are stable at 4°C, 25°C, 37°C and 40°C temperatures and have a pH of 7 and 8 respectively. The Minimum Inhibitory Concentration of M1 and M2 is 1% on P. myriotylum. M1 and M2 act on Pythium by membrane lysis, inhibiting proton pumps and inhibiting protein synthesis. The formulations M1 and M2 reduce the incidence of root rot disease in cocoyam plants growth in the greenhouse. M1 and M2 are potential candidates for improvement of cocoyam seedlings production in Cameroon.展开更多
基金Supported by the China Agriculture Research System(No.CARS-50)the National Natural Sciences Foundation of China(No.31372517)+2 种基金the Fundamental Research Funds for the Central Universities(No.201562018)the National Infrastructure of Fishery Germplasm Resources(No.2017DKA30470)the Project of Aoshan Scientific and Technological Innovation Program of Qingdao National Laboratory for Marine Science and Technology(No.2015ASKJ02)
文摘Pyropia yezoensis(formerly Porphyra yezoensis)is an economically important red alga that is cultured extensively in China.The red rot disease occurs commonly during Pyropia cultivation,causing serious economic losses.An incidence of red rot disease was found in a P.yezoensis farm from mid-November to mid-December 2015 at Lianyungang,Jiangsu Province,China.Histopathological examination revealed that the naturally infected thalli were infected apparently by a pathogen,leading to red rot symptoms.The causative agent was isolated and identified as the oomycete Pythium chondricola by morphological analysis and sequence analysis of the internal transcribed spacer and cytochrome oxidase subunit 1(cox 1).In artifi cial infection experiments on the P.yezoensis blades,the P.chondricola isolate was able to cause the same characteristic histopathology seen in natural infections.P.chondricola grew well at a wide range of temperatures in the range 8-31℃,salinities at 0-45 and pH 5-9.In an orthogonal test used to determine the effects of environmental factors(temperature,salinity,and zoospore concentration)on infection,the data revealed that temperature was the most important factor to affect red rot disease development,with the optimal conditions for disease expansion being 20℃,35 salinity,and a zoospore concentration of 10^6 zoospores/mL.The results obtained from the present study prompted us to set up a comprehensive epidemiological study on Pyropia,which will provide support to maintain the healthy development of the Pyropia industry in China.
文摘Three fungicide formulations, namely M1, M2 and M3, were prepared from sodium bicarbonate, citronella essential oil and sunflower slurry. The stability of M1, M2 and M3 formulations was determined based on pH, temperature, order of incorporation of the inputs and storage time. The most stable formulations were used for antagonistic tests on Pythium myriotylum. The Minimum Inhibitory Concentration (MIC) was used for the greenhouse tests and the mode of action was determined in vitro. The study showed that the order of incorporation of the inputs “Essential Oil-Tween 80-Bicarbonate-Slurry” (EO-T80-B-S) promotes stability. M1 and M2 are stable at 4°C, 25°C, 37°C and 40°C temperatures and have a pH of 7 and 8 respectively. The Minimum Inhibitory Concentration of M1 and M2 is 1% on P. myriotylum. M1 and M2 act on Pythium by membrane lysis, inhibiting proton pumps and inhibiting protein synthesis. The formulations M1 and M2 reduce the incidence of root rot disease in cocoyam plants growth in the greenhouse. M1 and M2 are potential candidates for improvement of cocoyam seedlings production in Cameroon.
