| This paper is mainly for soft rot and southern blight of konjac purification of pathogens, pathogenicity tests, biological characteristics, the use of biochemical and physiological identified by molecular methods of pathogenic microorganisms in different villages such as Guangming and LixinVillage, Langao County, Ankang City, Shaanxi Province. Specific conditions of the laboratory pathogens at different temperatures, different pH, different agents such as antibiotics, and under different growth conditions and differences in biological characteristics to test the performance of proposed control measures.The pathogenicity, morphological character and biological character of soft rot-causing bacteria, which isolated from Amorphalluskon jac growing in Langao county, Shaanxi province, were determined firstly. The results showed that the optimum temperature for these isolates were 25-30℃, but can't grow beyond 40℃. They can utilize glucose and lactose, but not maltose or starch or maltose. The test of pathogenicity to Konjac reavealed that the pathway to widely spread was by soil and infection was through cutting of plants. 16S rDNA sequence analysis of strains showed that they belonged to Pectobacterium sp. and were very closely related to Pectobacterium carotovora sub sp. carotovora, p.c.c. with 98.64% sequence identity. From line treatment, by species and temperature, pH and other tests under laboratory conditions, found in the handling of species of taro, taro on the kinds of processing time to grasp, no more than 1 hour. The best optimum growth of soft rot bacteria's pH range between pH5.0 ~ 8.0, other than the appropriate range of areas, particularly in the strong acid is more obvious. This bacteria of the original optimum growth temperature range between 25℃-30℃, the temperature range of above 38℃and below 6℃is not suitable, when the temperature below 5℃or above 40℃, the bacteria stopped growing.The southern blight-causing bacteria were isolated from Amorphalluskon jac collected in Langao county. The becteria were identified by an almost complete ITS gene sequence analysis together with the morphological and biological properties..The results showed that the optimum temperature and pH for these isolates were 25 to 35℃and pH 4-7, respectively. They can utilize glucose, lactose, maltose, galactose and mannitol as solely carbon resource, and use methionine, unrea, potassium nitrate, ammonium sulfate and peptone as solely nitrogen. The test of pathogenicity to Konjac reavealed that the pathway to widely spread was by soil and infection was through cutting of plants. The analysis of ITS sequences of strains showed that they belonged to Sclerotium rolfsii Sacc. , Agonomycetales, Hyphomycetes and Deuteromycotina.The pathogenic bacteria that cause sclerotium rolfsii disease have been determind by the ITS sequence analysis method. The results of this experiment will provide a theoretical basis for disease prevention.Prevention and control methods in biological research, mainly used to do 10 kinds of antibiotics susceptibility test, ampicillin was the best, followed by penicillin, chloramphenicol and Jinggangmycin.Screening of antagonistic bacteria in which the antagonistic effect of J-1 the most significant antagonistic mechanism requires further in-depth research, to provide biological control of konjac soft rot damage theory. |
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