Potential of bacterial indoleacetic acid to induce adventitious shoots in plant tissue culture

Aims: The main aim of this study was to investigate the possible role of indoleacetic acid (IAA) from bacteria to induce in vitro adventitious shoots in internodal explants of Brassica oleracea L. Methods and Results: Culture supernatant of Halomonas sp. RE1 and Halomonas sp. HT1 that contain 21 and 40 mu g ml(-1) IAA, respectively, was used to supplement Murashige and Skoog (MS) medium. Two combinations that were supplemented with bacterial supernatant (BS) are MS + BS and MS + BS + 10%CW (coconut water) while basal MS medium was used as control. The amounts of BS used in this experiment were 50, 100, 150 and 200 mu l in 5 ml MS medium in each combination. In vitro-grown internodal explants of B. oleracea were inoculated on these media combinations and incubated in a growth chamber at 25 +/- 1 degrees C and exposed to 16-h cool fluorescent light. After 5-6 weeks of incubation adventitious shoot induction was observed in all treatments that were supplemented with BS as compared with the controls where very low response was observed. The frequency of shoot induction was high in media that were supplemented with 10%CW in the presence of bacterial auxin. Conclusions: It was concluded that IAA of microbial origin has the potential to induce adventitious shoots in internodal explants. Significance and Impact of the Study: IAA from bacteria can be effectively used in plant tissue culture; especially a combination of MS + BS + 10%CW is very cost-effective as compared with synthetic phytohormones for in vitro studies.