The Mechanism Of Disease-Resistant Varieties To Banana Fusarium Wilt Disease And The Effects On Soil Microbial Community Structure

Banana production has been severely hindered by Fusarium wilt disease, caused by the Fusarium oxysporum f.sp.cubense (FOC), selecting disease-resistant varieties is one of the important countermeasures to control the Fusarium wilt disease. In this study,frist studied the changes of defence enzymes and soil culturable microorganisms after inoculated with different concentration of pathogenic based on pot experiment.Then analyzed by PCR-DGGE and MiSeq platform to study the soil microbial community structure and diversity of cultivars with different resistance. Discusses the resistance mechanism of disease-resistant varieties and the effects on soil microbial community, aimed to provide theoretical basis for breeding Banana varieties which can resistant Fusarium wilt disease.The main results are as follows:(1) The resistance and mechanism of disease-resistant varieties to banana Fusarium wilt disease.When inoculated with different concentration FOC4, The incidence of'Bao dao218'and'nan tian huang'increased with the concentration increasing in pot experiment.When the concentration of spore suspension of 103cfu/gsoil, the incidence of baxijiao'is 40%,at the same time the incidence of disease-resistant varieties is approximately 5%. When the concentration of spore suspension of 104cfu/gsoil, the incidence of baxijiao'is 90%,at the same time the incidence of disease-resistant varieties is 25% and 20%. When the concentration of spore suspension of 104cfu/gsoil, the incidence of disease-resistant varieties is achieved 55% and 45%.The results consistent with field survey,it shows that, the amount and accumulationof FOC4 are not related to the banana varieties.And the study shows that,the water extract of banana residue could promote the growth of FOC4 myceli and improve the rate of spore germination, but each strain is slightly different.(2) The physiological resistance mechanisms of varieties which resistant to banana fusarium wilt disease.When inoculated with FOC4, POD activity of each variety are improved,'Bao dao218'a nd 'nan tian huang' POD activity are changed greater than'baxijiao'.PPO activity of each variety are all improved, and'Bao dao218' and'nan tian huang'POD activity are higher than'baxijiao'. The chitinase and ?-1,3-glucanse activity of disease-resistant varieties are higher than'Baxijiao', The ?-1,3-glucanse activity of disease-resistant varieties is there times as high as'baxijiao'. Prove that the resistance of the banana have a positive correlation with the activity of PPO?POD?chitinase and ?-1,3-glucanse? The Change of PAL activity are identical,at the same time, there is a obvious different between Bao dao218'and'Baxijiao',shows that there are correlation between PAL activity and disease resistance of banana.(3) The effects of disease-resistant banana varieties on soil microbial?The abundance of fungi in disease-resistant varieties less than that in'Baxijiao', The abundance of bacteria in disease-resistant varieties more than that in'Baxijiao'? The soil bacterial and fungal communities of field experiment were analyzed using MiSeq platform to investigate the effect of disease-resistant banana varieties on soil microbial. Disease-resistant varieties soil revealed higher abundances of Basidiomycota?Zygomycota? Bacteroidetes?Actinobacteria and Firmicutes; Disease-resistant varieties soil revealed lower abundances of Ascomycota?Fibrobacteres and Chloroflexi? The abundances of Fusarium has no difference between disease-resistant varieties and'Baxijiao'.