2020 Volume 64 Issue 1 Pages 1-6
In our previous experiment, water yam (Dioscorea alata L.) was able to grow under low-fertility soil conditions and nitrogen in the plant was found to be derived from the air. Moreover, some genera of nitrogen-fixing bacteria (NFB) were subsequently isolated. The objective of this study, therefore, was to confirm and identify the infection route of NFB in water yam plants. Plants were grown in pots with sterilized river sand (control) or river sand plus non-sterilized soil (treatment) in an artificial climate chamber. The soil used was the same as that used in our previous experiment in which NFB were isolated. Control and soil-treated plants were grown till harvest at 120 days after planting under no-fertilizer conditions. Endophytic NFB were isolated from the roots, vines, and leaves of control and treatment plants. Fourteen genera of NFB endophyte were identified after culture on SMM-N and MR media. The results suggested that NFB infect water yam plants via the soil, seed tubers, or airborne transmission. The seed tuber surface was subsequently sterilized with fungicide, and the results suggested that the NFB were transmitted via the air or from inside the seed tuber. This is the first report to identify the bacterial infection route in water yam plants.
