Resistance Identification Of Banana Cultivars Against Banana Fusarium Wilt And The Analysis Of Soil Microbial Community Structure Of Banana Rhizosphere

Banana,family Musaceae,genus Musa,is a perennial monocotyledonous plant,which is one of the most important tropical crops in the world and one of the four popular fruits in south C hina.It is the main source of income for many developing countries.Banana wilt,caused by the race 4 of Fusarium oxysporum f.sp cubense race 4,is the most serious disease in banana production,which almost infects all the banana cultivation areas around the world,causing damage to the banana quality and yield.The selection and promotion of resistant cultivars is a fundamental way to control banana wilt disease.In this study,several resistance cultivars to Fusarium wilt that are new selection and cultivation on the recent production were evaluated by conventional inoculation methods.And then the community diversity of soil edaphon in banana rhizosphere for healthy and inoculated with different concentrations spores of Fusarium oxysporum f.sp.cubense(FOC)were analyzed by Terminal Restriction Fragment Length Polymorphism(T-RFLP)and plate count.Through the research to understand the effect of same banana cultivars with different concentrations spores of FOC on soil edaphon population and community diversity,and the differences of soil microbial community diversity in banana rhizosphere between the disease-resistant cultivars and susceptible cultivars,so that to provide a scientific basis for the biological control against fusarium wilt.The key findings are as follows:The results showed that the six different cultivars were not immunized with different concentrations spores of FOC,which exist the concentration-dependent resistance of pathogen fungi.But there are significant differences between different cultivars.The resistance of them from strong to weak followed by:’Pisang Empat Puluh Hari‘,’Yueke‘,’Agricultural one‘,’Skyyellow‘,’Skyred‘,’Brazil banana‘.Which are divided according to the resistance evaluatio n standard of banana cultivars(the disease index of moderate resistance is from 16.00 to 29.99).’Pisang Empat Puluh Hari‘can resist the concentration of pathogen fungi is 10~6 cfu/mL,’Yueke‘can resist the concentration of pathogen fungi is10~5 cfu/mL,both the’Agricultural one‘and’Skyyellow‘can resist the concentration of pathogen fungi is 10~4 cfu/mL.In this research using plate count method to analysis the number of bacteria,actinomycetes and FOC in the soil samples of banana plant roots.The results indicated that the number of cultivable bacteria and actinomycetes decreased with the increase of inoculation concentration,and the number of FOC increase significantly with the growth of inoculation concentration.The quantities of cultivable bacteria and actinomycetes in the disease-resistant cultivars are much higher than that of the susceptible cultivars.The quantities of cultivable bacteria and actinomycetes in inoculated banana plants are higher than those in the untreated healthy control gro up(CK),and the number of pathogenic fungus FOC in the susceptible cultivars are significantly higher in disease-resistant cultivars.Using BIOLOG method to analysis that the microbial community functional diversity of different cultivars and different inoculated banana rhizosphere soils.The results showed that the microbial community functional diversity of soil samples in the same cultivars decreased with the growth of inoculation concentration,and the microbial community functional diversity of soil samples of disease-resistant cultivars"Haigong"are higher than those of susceptible cultivars"Brazilian banana".In this research bacterial community diversity of different cultivars and different inoculated banana rhizosphere soils were analyzed by Terminal Restriction Fragment Length Polymorphism(T-RFLP),The results show that the diversity of bacteria community in the root rhizosphere soil of the disease-resistant cultivars was more abundant than that of the susceptible cultivars,and the bacteria community diversity in the soils of the banana root rhizosphere inoculated with the FOC are higher than those in the inoculated.In the same cultivars of banana plants,with the increase of the FOC concentration,the soil bacterial diversity index and the ric hness index is decreasing and the abundance of dominant bacteria community is increasing.There are differences between the disease-resistant cultivars and susceptible cultivars of the abundance of dominant bacteria in the banana root rhizosphere soils.The abundance of dominant bacteria of various banana cultivars is increasing with the time of 10th day,20th day and 30th day after inoculating.The above three kinds of microbial determination methods all indicate that the number of cultivable bacteria and actinomycetes decrease with the increase of inoculation concentration.The quantities and diversity of cultivable bacteria and actinomycetes in the disease-resistant cultivars are much higher than those of the susceptible cultivars,and the abundance of dominant bacteria of various banana cultivars is increasing over time after inoculating.