Piper nigrum, commonly known as black pepper, is one of the most important spice crops
with high demand by the world market. However, diseases like foot rot and stem blight
cause by Phytophthora capsici have become the important production constraints in black
pepper industry. The frequent application of toxic fungicides to counter the diseases in pepper
plantations has raised certain environmental issues. In order to mitigate the use of fungicides,
biological approach to control P. capsici has been suggested. In this study, endophytic bacteria
were isolated from six P. nigrum roots and screened for in vitro antagonistic activity against P.
capsici through dual culture, mycelial growth, spore germination and double plate assay. The
antagonism testing involved the secretion of volatile and diffusible bioactive compounds by
the endophytic bacteria. Out of 19 isolates tested, two isolates DB(2)7 and SB(2)6 produced
volatile bioactive compounds and these two isolates showed highest antagonism against P.
capsici mycelia with the percentage of inhibition up to 47.63% and 43.33%, respectively.
Diffusible compounds from isolates DB(2)7, DB(2)9 and SB(2)6 produced clear zones in spore
germination test with radii measurements of 10.0-17.0 mm. Three isolates with promising
antifungal activity were further characterised through 16S rDNA sequencing. The analysis
of their sequences via National Center for Biotechnology Information (NCBI) suggests close
identity towards Enterobacter cancerogenus, Enterobacter cloacae and Enterobacter asburiae.
This research study demonstrated that these endophytic bacteria isolates are potentially to be
used as biocontrol agent in pepper cultivation.