title: Culturable bacterial endophytes isolated from Mangrove tree (Rhizophora apiculata Blume) enhance seedling growth in Rice.
abstract: BACKGROUND
  Endophytic bacteria do have several potential applications in medicine and in other various sectors of biotechnology including agriculture. Bacterial endophytes need to be explored for their potential applications in agricultural biotechnology. One of the potential applications of bacterial endophytes in agricultural is to enhance the growth of the agricultural crops. Hence, this study was undertaken to explore the plant growth promoting potential application of bacterial endophytes.
  
  
  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.
  
  
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Biotechnology, Faculty of Applied Sciences, AIMST University, Semeling, Kedah, Malaysia.
authors.forename: Subramanian
authors.initials: S
authors.lastname: Deivanai
authors.affiliation: Department of Biotechnology, Faculty of Applied Sciences, AIMST University, Semeling, Kedah, Malaysia.
authors.forename: Amitraghata Santhanam
authors.initials: AS
authors.lastname: Bindusara
authors.affiliation: Department of Biotechnology, Faculty of Applied Sciences, AIMST University, Semeling, Kedah, Malaysia.
authors.forename: Guruswamy
authors.initials: G
authors.lastname: Prabhakaran
authors.affiliation: Department of Biotechnology, Faculty of Applied Sciences, AIMST University, Semeling, Kedah, Malaysia.
authors.forename: Subhash Janardhan
authors.initials: SJ
authors.lastname: Bhore
keywords: 16S ribosomal deoxyribonucleic acid; Rhizophora apiculata; bacteria; bioprospecting; endophytes; mangrove; rice
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