Identification and Characterisation of Endophytic Bacteria from Coconut (Cocos nucifera) Tissue Culture

The coconut is an important economic crop in the Philippines which currently ranks as the world's second largest producer. This study characterised and identified endophytes from coconut tissue culture in order to gain an initial understanding of their potential uses as sources of bioproducts. The isolates were evaluated using morphological, biochemical and molecular methods. Gram staining results revealed that four out of five bacteria isolated were Gram positive. Isolate CEB 1 fermented all three sugars in the Triple Sugar Iron Test while the other four did not. 16S rDNA gene fragments were amplified from genomic DNA using the universal primers 16F27 and 16R1542. The 16S rDNA sequence were found to be homologous to Bacillus subtilis and Pantoea dispersa. Phylogenetic analyses showed significant clustering of bacterial isolates together with archived DNA of B. subtilis and P. dispersa. All isolated bacteria matched the characteristics of their molecular homologies. Isolate CEB 5, identified as B. subtilis, produced red pigments which are possibly pulcherrimin. Literature reports that pulcherrimin possesses antimicrobial activity against yeast species, microscopic fungi, and postharvest pathogens. P. dispera, on the other hand, has been reported to convert insoluble phosphorus into soluble form to enable plants to take up more phosphorus. Determination of the bioactivities of endophytes reported in this study may enable the discovery of novel bioproducts.