Characterization of Bacillus subtilis HC8, a novel plant-beneficial endophytic strain from giant hogweed

Thirty endophytic bacteria were isolated from various plant species growing near Saint-Petersburg, Russia. Based on a screening for various traits, including plant-beneficial properties and DNA fragment patterns, potential siblings were removed. The remaining isolates were taxonomically identified using 16S rDNA sequences and potential human and plant pathogens were removed. The remaining strains were tested for their ability to promote radish root growth and to protect tomato plants against tomato foot and root rot. One strain, Bacillus subtilis HC8, isolated from the giant hogweed Heracleum sosnowskyi Manden, significantly promoted plant growth and protected tomato against tomato foot and root rot. Metabolites possibly responsible for these plant-beneficial properties were identified as the hormone gibberellin and (lipo)peptide antibiotics respectively. The antibiotic properties of strain HC8 are similar to those of the commercially available plant-beneficial strain Bacillus amyloliquefaciens FZB42. However, thin layer chromatography profiles of the two strains differ. It is speculated that endophytes such as B. subtilis HC8 contribute to the fast growth of giant hogweed.