Comparative Study of the Colonization of Chromolaena and Tobacco Plants by Bacteria safensis CS4 using Different Methods of Inoculation

This study entails the effectiveness of colonization of bacterial endophytes following inoculation of the cells in plants.

Different methods of inoculation including seed immersion, root immersion and foliar spray were studied on Chromolaena odorata and Nicotiana tabacum for 10, 20 and 30 days. This was to ascertain the colonization ability of the endophytic strain amongst the two set of plants. The foliar parts of the plants were assessed post inoculation for the presence of the bacteria strain, followed by the growth parameters in the plant. Significant differences at p<0.05 of colonization were established by the different inoculation methods.

Foliar spray demonstrated the highest colonization in both Chromolaena and tobacco plants followed by root immersion. Leaf inoculation in tobacco plant demonstrated a positive colonization which is not significant. However, seed inoculation provided colonization in Chromolaena plant at 10, 20 and 30 days post inoculation at a frequency lower than that of tobacco. With root immersion in Chromolaena, there was colonization at 10 days post inoculation, no colonization at 20 days post inoculation, but colonization re-appeared at 30 days (PI). Growth index measured demonstrated a positive relationship between the inoculation of the endophyte and the growth parameters which included stem length and germination rate.

This study, therefore, showed that the bacteria strain B. safensis CS4 can effectively be horizontally transferred into tobacco and Chromolaena plants using different methods. Foliar spraying demonstrated the optimal colonization of the strain in the plant leaves.