Antibacterial and phosphate solubilization activity of endophytic bacteria isolated from Pterydophyta (Tectaria barberi)

Abstract

Endophytic bacteria have been isolated from many plants and their contribution to host plants have been proposed by many researchers, such as preventing plant from pathogens, producing plant growth hormones, producing bioactive compounds, solubilizing phosphate, etc. However, the study of endophytes of pioneer plant such as fern is very limited. The objective of this study was to obtain potential endophytic bacteria from fern Tectaria barberi and to measure their ability to inhibit the growth of human pathogenic bacteria (Escherichia coli (EPEC), Staphylococcus aureus ATCC 29213, Listeria monocytogenes BTCC B693, Methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300, Staphylococcus epidermidis ATCC 12228, and Proteus vulgaris ATCC 13315). The ability of isolates in solubilizing phosphate was measured to learn possible role of endophytes for the plant. Six endophytic bacteria were obtained. Antagonistic test indicated all isolates inhibited the growth of tested pathogens to some extends. Isolates EPS36 showed the highest inhibition activity against EPEC (with inhibition zone 8.6 mm). The isolate also inhibited the growth of S. aureus and S. epidermidis by 6.1 and 6.6 mm, respectively. EPS37 inhibited the growth of S. aureus by 6.1 mm, EPS02 inhibited P. vulgaris (5.6 mm), EPS42 to L. monocytogenes (5.7 mm), and EPS21 inhibited MRSA (5 mm). Qualitative screening of isolates in Pikovskaya media after 24 hours incubation showed that EPS41, EPS36, and EPS37 formed clear zone surrounding the colony indicating their ability to solubilize phosphates. As far literatures has been surveyed, this is the first study of endophytes bacterial isolates from pteridophytes in the country, and a lot more is needed in order to elaborate the role of endophytes from this plant.