For in vitro colonization to be quickly verified, substrate transparency is important. With this objective, a simple method was modified and the visualization of rhizobacteria in the roots was correlated to their colonization via scanning electron microscopy (SEM). Seeds of Citrus limonia Osbeck were inoculated and monitored in glass tubes with different substrates (Agar-Agar, Agar Noble and Phytagel). Seven rhizobacteria strains were evaluated, and an isolate of Escherichia coli DH5a was used as the negative control. Phytagel allowed a clearer visualization of the colonization along the roots by the bacteria and a higher sensibility for the confirmation of the rhizobacteria. Roots that presented turbidity around the agar exhibited an efficient surface colonization when observed in high magnification. This method showed to be a very good tool to study the root colonization via SEM.
Citrus limonia; rhizobacteria; root colonization