Study On Screening Of Bacteria For Ginseng Pathogenic Fungical Disease And Effect Of Ginseng Disease Control

Ginseng is the traditional chinese medicinal material in the treasure house of chinesemedicine in China. With the continual deepening of the research on ginseng’s medicinal values,the distribution density of wild ginseng has sharply decreased, thus resulting in the increasinglyprominent problems such as wild resources protection and contradiction between supply anddemand. Since ginseng cultivation has a long history in China, the artificial cultivation, to acertain extent, alleviates the pressure of the supply and demand market. However, due to theimperfection of the ginseng tending technique today, which in turn brings about the frequentginseng fungal disease problem, the yield of ginseng still cannot be guaranteed. At present, theprevention and treatment of plant diseases are done mainly by artificial chemicals, which canhave certain effect in the short term. Nevertheless, drug resistance as a result of long-term use ofchemicals will lead to reducing control effects and then the decline in ginseng’s quality. What’smore, the output of ginseng will be influenced because of the soil microenvironment imbalancecaused by excess chemicals. Therefore, in view of the urgent demand of the market for thequalities and production of ginseng, attention has been turned to the biological controlapproaches.In order to obtain the efficient biological control bacteria for ginseng fungal diseases,the biological control bacteria of ginseng pathogenic fungi are selected and identified, and thenthe growth-promoting and disease prevention affects of biological controlling bacteria onginseng are discussed. The main results are as follows:1. The rhizosphere soil samples of healthy ginseng were collected from the standardizedginseng cultivation base in Wanliang Town, Fusong County, Jilin Province, from May toSeptember in2012,289kinds of bacteria were isolated. These bacteria were antagonisticallyselected in vitro on the cultivation plates,12bacteria which have obvious antagonism affects onginseng pathogenic fungi were selected by the filter paper method and oxford cup method. Theinhibitory affects of the12antagonistic bacteria on fungi were tested. The result shows that theinhibition rate of each antagonistic bacterium on ginseng pathogenic fungi varies from53.0%to96.33%; the antagonistic bandwidth range that bacteria fermentation filtrate shows is between5.07-15.0mm.2. the traditional antibiotics labeling method is used and two circumstances of natural soiland sterile soil are set, the rifampicin resistant mutant strains’colonization ability of biocontrolbacteria SZ-3, SZ-4, SZ-22, SZ-34, SZ-56, SZ-60and SZ-81is tested in the ginseng cultivation soil and ginseng plants. The colonization ability test shows:7of them have good colonizationability in ginseng cultivation soil and ginseng plants, the amount of every bacterium in the soilshows the trend of “down, up, down”, SZ-81disappeared in the30thday, and the level of otherbacteria keeps at104fu/g stably; all of the7biological bacteria have largest colonization amountin the roots of the ginseng plants, and less in the stems, and has least amount in the leaves, itbasically shows the trend of “increase first and then decrease”, with time going by, thereproduction ability of the7bacteria still keep at a certain level stably, which shows a greatcolonization ability. In addition, we can still isolate certain amount of bacteria from the roots ofginseng in the20thday, which indicates that the bacteria can colonize in the ginseng root withoutcausing disease.3. The root perfusion method is used to conduct the greenhouse disease prevention test onbiocontrol bacteria, it shows that the control effect of the7biocontrol bacteria is at the samelevel with or better than that of the pesticides group. The best control effects on ginseng root rot,ginseng black spot, ginseng blight, ginseng rust rot, ginseng sclerotinia and ginseng botrytis are58.56%,58.14%,73.94%,63.02%,78.06%,65.89%,63.06%perspectively, which are betterthan that of pesticides group. The difference analysis indicates that the difference betweenbiocontrol bacteria and pesticides group is significant at the level of P <0.05, and the differenceis extremely significant at the level of P <0.01.4. The traditional method and molecular biological method are applied to conductpreliminary identification on5biocontrol bacteria which have good biocontrol effect.Morphology, physiology and biochemistry, and16SrDNA gene sequence analysis show thatbacterium SZ-3belongs to bacillus methylotrophicus, bacterium SZ-4belongs to bacillusvallismortis, bacterium SZ-22is brevundimonas terrae, bacterium SZ-56belongs to bacillusendophyticus, bacterium SZ-60belongs to bacillus amyloliquefaciens. Currently, the bacteriarelated to fungal disease control, which have been reported, are mainly genus pseudomonasbacteria and bacillus subtilis. The application on ginseng fungi disease control frombrevundimonas terrae which shortwave single cell belongs to and bacillus methylotrophicuswhich bacillus belongs to, bacillus amyloliquefaciens, bacillus vallismortis have never beenseen reported. The5biocontrol bacteria obtained provide new materials for the biologicalcontrol on semi-ginseng fungal diseases.