Identification To The Pathogen Of Banana Fusarium Wilt And Screening The Antagonistic Bacteria Against It

As a destructive soil-borne diseases caused by Fusarium oxysprum f.sp.Cubense race 4,banana fusarium wilt has sporadically happened and the pathogen are accumulating.So far,the chemical prevention against banana Fusarium wilt is not effective enough and the biological control could reduce the use of chemicals,improve the ecosystem in the field,maintain the biodiversity of the system,which is a sustainable way.In the research,the pathogen of the suspected banana fusarium wilt samples are identified as FOC4.The antagonistic bacteria are isolated from the the banana tissue like root,leaf,corm and cauloid.They are screened by the confront culture with the pathogen.30 strains of antagonistic bacteria are gotten by this way.They are classified as 3 classes which include Bacillus subtilis、Paenibacillus polymyxa、Bacillus licheniformis by the analysis of the 16SrDNA sequence.By testing the fungistasis of the metabolin from some isolated strains like J3-3、J6-1、J7-1,XJ18、XY9、XG2 of which the antifungal activity are relatively stable,the J3-3 and XJ18 are found.Their fungistasis is beyond 90%.They are identified as Bacillus subtilis by the analysis of the 16SrDNA sequence and the test of their physiological and biochemical indexes.The bacteria can use melibiose,raffinose,sorbitol,sorbose,mannitol,mannose,lactose,D-glucose,L-arabinose,D-xylose as carbon source.The bacteria growth relatively well in the culture solution containing 4%soyabean expeller and 2%molasses.The peak value of the growth appears on the time between 15th day and 20th day.This culture solution has a good fungistasis on plate,however,the metabolin from the solution is far less than the NA solution.On the potted plant,the antifungal effect between the two solution have no significant difference.The antifungal effect of experimental group(the inoculation after curing)is beyond 40%.