PLANT CELL BIOTECHNOLOGY AND MOLECULAR BIOLOGY

Pneumatophores of mangrove plants are biodiversity “hotspots” of microfauna, harbouring epiphytic and endophytic symbionts. This study is aimed at isolating and identifying endophytic bacteria from the pneumatophores of the mangrove plant Avicennia officinalis, from the mangrove ecosystem of Poovar, South Kerala, India. The pneumatophore endosphere was visualised using Scanning Electron Microscopy and mineral composition was determined using Energy Dispersive X–ray Analysis (EDAX). Endophytic colonies were isolated from the extract of surface sterilized pneumatophore samples and four bacterial colonies with distinct colony morphology but atypical biochemical pattern were propagated in pure culture and their 16srRNAs were sequenced and aligned with standard genomic sequences for taxon assignment. The colonies isolated were identified as Pseudomonas alcaligenes (PMB1) and Aeromonas taiwanensis (PMB3 & PMB4). The sequence data of the isolate encoded PMB2 had less than 95% similarity with the standard 16S rRNA sequences available in GenBank and the novel sequence was deposited in the NCBI Library under the accession number MT 671484. The occurrence of novel genomes, the identification of Pseudomonas alcaligenes with bioremedial potential and Aeromonas taiwanensis with antibiotic resistance plasmids from the pneumatophore of Avicennia officinalis throw light into this hithero unexplored hidden treasure of novel yet- to- be- cultured bacteria within the sequestrated microhabitats of mangrove ecosystems. The study emphasise the need of further investigations        in this aspect to fully exploit the beneficial biotechnological potential of pneumatophore endobacteria.