The Construction Of The Hydroponics Pathogenic System And Knock-out Of FOC4B-007Gene In Fusarium Oxysporum F.Sp.Cubense

Banana Fusarium wilt disease, caused by the filamentous fungus Fusarium oxysporum f. sp. Cubense (Foc), is one of the most devastating soil born banana diseases. The complex soil environment brought obstacles in studying pathogenesis mechanism research before. In order to do further study in the interaction mechanism between banana and FOC, the banana seedlings hydroponics pathogenic system was used for technical support. Then selected FOC4B007gene which was resumed to be ATP-binding transporter from the gene bank of Fusarium oxysporum f. sp. Cubense race4(FOC4) by analysising the encoded amino acid sequence. Pathogenie-related deletion mutant B-007, ALS, ste12, Ceg-1, Ceg-2were observed and analysised by hydroponics pathogenic system. The main results were showed as followings:1. The optimal culture substrate of Baxi banana in static water cultuer was BXM nutrient solution, the best ionic strength of Baxi banana in static water cultuer was2BXM, the most suitable PH of Baxi banana in static water cultuer was6.0, and the most appropriate replacement cycle of nutrient solution was10d. All these conditions were obtained by analysising the banana weight, height, and the leaf area.2. Two integrated vectors used to knock-out B007gene were constructed by gene splicing with backbone plasmid pCX62. Seven transformants were abtained by using the method of PEG protoplast transformation. Then4expressions were detected using4pairs primers PCR and RT-PCR method.3. The mutant and the wild-type strains had no significant difference in oolony morphology, spore morphology, and pathogenicity to banana. The mutant strains were growing more slowly than the wild-type strains. The wild-type strains showed resistance to Trichoderma in the confrontation experiment, but the mutant strains showed lower resistance to Trichoderma in the experiment. The result was that B007gene played a role in the interaction of FOC4and other fungi.4. The regular pattern of the growth of Fusarium oxysporum f. sp. cubense in nutrient solution and soil solution was approaching. The concentration of FOC was106cfu/ml, and the pathogenic cycle was20-25d in the hydroponics pathogenic system. The results of hydroponics pathogenic method and soil culture method had no significant difference.5.The results of hydroponics pathogenic method and soil culture method for analysising the pathogenicity to banana with the mutant and the wild-type strains had no significant difference. The hydroponics pathogenic system could be used to analysis the pathogenicity of FOC quickly and exactly.