Abstract:

The endophytic bacteria against banana fusarium wilt from banana were isolated in order to study the biocontrol of banana fusarium wilt. Bacteria were isolated from the corm of healthy banana, and their antagonistic abilities to Fusarium oxysporum f.sp cubense race 4 (Foc 4) were respectively determined. KKWB-10 strain exhibiting excellent resistance against Foc 4 was identified by morphological, physiological and 16S rDNA gene sequence. A GFP-labeling KKWB-10 strain K-pUCK7-1′GT was inoculated into banana tissue culture plantlets using the root dipping method. After 10 days of growth, freehand sections of the stems and roots of these banana plantlets were observed by laser confocal scanning microscope. The results of antagonistic experiments showed that KKWB-10 strain was an antagonistic bacterium that exhibited excellent resistance against Foc 4. The strain was primarily identified as Enterobacter cloacae based on the results of its 16S rDNA gene sequence homology, the physiological and morphological characteristics. Green fluorescence was observed in the roots and stems of banana plantlets inoculated with GFP-labeling KKWB-10 strain, but not in uninoculated controls. The result suggested that the KKWB-10 strain could colonize the roots and stems of banana plants. The KKWB-10 strain can be used as not only biocontrol agents but also vectors for the introduction of heterologous resistance genes into banana plants. Thus the KKWB-10 strain would be a potential natural resource for the biological control of banana fusarium wilt.