Culture-Dependent Analysis of Endophytic Bacterial Community of Sweet Potato (Ipomoea batatas) in Different Soils and Climates

Aims: To examine the effects of soil and climatic conditions on community structure of the sweet potato bacterial endophytes.

Study Design: Sweet potato plants were cultivated in different soils and locations combinations and the endophytic bacterial isolates from the tubers were examined to clarify the effect of soil and climatic conditions on the microbial community.

Place and Duration of Study: The plants were cultivated in Fukagawa, Matsue and Miyazaki in Japan for ca. 3 months.

Methodology: Bacterial isolates were characterised based on their morphologies and the representative colonies were purified for identification by analysing the partial 16S rRNA gene sequences. Endophytic bacterial community was analysed based on phylum/class and genus levels.

Results: Sixty two colonies were isolated and identified. γ-Proteobacteria (96%), β-Proteobacteria (87%) and Actinobacteria (88%) dominated in the samples cultivated in Fukagawa, Matsue and Miyazaki soils at the corresponding locations, respectively. When the soil samples were used in the different locations, the above mentioned location-specific phyla increased at the new sites. The endophytic bacterial population was also affected by the cultivating locations. It was suggested that the location rather than the soil influenced on the endophytic community and population.

Conclusion: The cultivating locations were more important factor than the soils to determine the sweet potato endophytic bacterial community and population.