Potential of Karimunjawa Island’s Plants as Antibiotic-Producing Endophytic Bacteria Sources

Abstract

Endophytic bacteria have a great potential to be applied as biofertilizers and biopesticides, but their information as a source of antibiotics still needs to be developed and explored. The aim of this study was to investigate the potential sources of antibiotics in endophytic bacteria isolated from the stems of Setigi, Wahong, Bongko, Kalimosodo, Dewandaru, and Legundi plants on Karimunjawa Island. Molecular approaches were performed to isolate, characterize, and identify bacterial endophytes as potential antibiotic sources by plate assay and 16S rRNA gene sequence analysis. Dewandaru isolate was identified as gram-negative bacteria, whereas; gram-positive bacteria were detected in other isolates. Moreover, Setigi and Dewandaru isolates showed the highest level to inhibit the growth of Fusarium sp and displayed 99% similarity with antibiotic-producing bacteria, namely Bacillus pumilus and Bacillus cereus, respectively. These results indicate the possibility of antibiotic activities by Setigi and Dewandaru isolated. Therefore, it is assumed that both Setigi and Dewandaru isolates potentially appeared as new antibiotics sources from local plants. This study provides novel insight into the future production of novel antibiotics derived from plant-associated endophytic bacterial as a strategy for increasing the application of natural compounds to control plant diseases in agriculture.