OBJECTIVE: The objective of this study was to examine the effect of endophytic bacteria from mangrove tree (Rhizophora apiculata Blume) for their efficacy in promoting seedling growth in rice.
MATERIALS AND METHODS: Eight endophytic bacterial isolates (EBIs) isolated from twig and petiole tissues of the mangrove were identified based on their 16S ribosomal ribonucleic acid (rRNA) gene sequence homology. Separately, surface sterilized paddy seeds were treated with cell-free broth and cell suspension of the EBIs. Rice seedlings were analyzed by various bioassays and data was recorded.
RESULTS: The gene sequences of the isolates were closely related to two genera namely, Bacillus and Pantoea. Inoculation of EBIs from R. apiculata with rice seeds resulted in accelerated root and shoot growth with significant increase in chlorophyll content. Among the isolates, Pantoea ananatis (1MSE1) and Bacillus amyloliquefaciens (3MPE1) had shown predominance of activity. Endophytic invasion was recognized by the non-host by rapid accumulation of reactive oxygen species (ROS) and was counteracted by the production of hydrogen peroxide (H2O2) and lipid peroxide. The results demonstrated that EBIs from mangrove tree can increase the fitness of the rice seedlings under controlled conditions.
CONCLUSION: These research findings could be useful to enhance the seedling growth and could serve as foundation in further research on enhancing the growth of the rice crop using endophytic bacteria.
OBJECTIVE: The objective of this study was to investigate the fast growing and cultivable BEs associated with T. procumbens.
MATERIALS AND METHODS: Leaves and stems of healthy T. Procumbens plants were collected and cultivable BEs were isolated from surface-sterilized leaf and stem tissue samples using Luria-Bertani (LB) agar (medium) at standard conditions. A polymerase chain reaction was employed to amplify 16S rRNA coding gene fragments from the isolates. Cultivable endophytic bacterial isolates (EBIs) were identified using 16S rRNA gene nucleotide sequence similarity based method of bacterial identification.
RESULTS: Altogether, 50 culturable EBIs were isolated. 16S rRNA gene nucleotide sequences analysis using the Basic Local Alignment Search Tool (BLAST) revealed identities of the EBIs. Analysis reveals that cultivable Bacillus spp., Cronobacter sakazakii, Enterobacter spp., Lysinibacillus sphaericus, Pantoea spp., Pseudomonas spp. and Terribacillus saccharophilus are associated with T. Procumbens.
CONCLUSION: Based on the results, we conclude that 24 different types of culturable BEs are associated with traditionally used medicinal plant, T. Procumbens, and require further study.
ABBREVIATIONS: gDNA - Nuclear genomic DNA, GSSs - Genome survey sequences K12, SAOP - South American oil-palm Db1.
RESULTS: One hundred and twenty RAPD primers were screened through RAPD-PCR against a panel of common enterobacteriaceae for the best RAPD band pattern discrimination to develop SCAR primers that were used to develop a RAPD-SCAR PCR. Of this number, 10 were selected based on their calculated indices of discrimination. Four RAPD primers, SBSA02, SBSA03, SBSD08 and SBSD11 produced suitable bands ranging from 900 to 2500 bp. However, only SBSD11 was found to be specific for S. Typhi, and was cloned, sequenced and used to design new SCAR primers. The primers were used to amplify a panel of organisms to evaluate its specificity. However, the amplified regions were similar to other non-Typhi genomes denoting a lack of specificity of the primers as a marker for S. Typhi.