Diversity analysis of endophytic bacteria withinAzolla microphyllausing PCR-DGGE and electron microscopy

Using 16S rDNA-polymerase chain reaction–denaturing gradient gel electrophoresis (PCR-DGGE), electron microscopy and a conventional plating method, the genetic diversity and phenotype polymorphism of the endophytic bacteria withinAzolla microphyllawere explored. The 16S rDNA-PCR-DGGE profile showed a complex and divergent bacterial community, withBacillus cereusas the dominant species, within theAzolla–cyanobacteria association. This result was supported by the fact that endobacterial cells exhibited distinct ultrastructural characteristicsin vivoand,in vitro, bacteria displayed various colonies with different sizes, shapes and colours. This study demonstrates that the genetic diversity of endophytic bacteria inAzollacan be investigated using the16S rDNA-PCR-DGGE technique.