Species specific primers of P. fluorescens and B. subtilis amplified the respective bacterial DNA fragments of ~500 bp and 400 bp ( Fig. 3; lanes 2 and 6). DNA from roots of untreated seedlings showed no amplification in both cases where P. fluorescens and B. subtilis primers were used (lanes 1 and 5). When DNA from roots of seedlings treated with both the bacteria, the primers yielded respective expected size amplification (lanes 3 and 7) indicating the presence of both bacteria inside the root tissues.