Assessment of the Osmotolerant Endophytic Bacteria from Mustard and Nagphani for their Plant Growth Promoting activities under Osmotic stress Rathi Maheshwar Singh1,*, Paul Sangeeta1, Choudhary Devender2, Kumar Manoj2, Chandra Anil2, Kharkwal Amit C.2, Varma Ajit2 1Division of Microbiology, Indian Agricultural Research Institute, New Delhi-110 012, India 2Amity Institute of Microbial Technology, Amity University, Noida-201313, Uttar Pradesh, India *Corresponding author: Division of Microbiology, Indian Agricultural Research Institute, New Delhi-10012, India. Email: talk2msrathi@gmail.com
Online published on 11 January, 2019. Abstract The present investigation was conducted to determined the effect of osmotic stress on plant growth promoting activities of the osmotolerant endophytic bacteria. Osmotic stress led to a decrease in growth of both the endophytic Bacillus aryabhatti strain NSRSSS-1 and Bacillus sp. strain MKS 6. However, supplementation of the medium with 40% PEG 6000 led to drastic reduction in growth of both the cultures. Both endophytic bacterial strains were found to improve seed germination, plumule and radicle length under severe stress conditions. Effect of osmotic stress on plant growth promoting activities of the selected osmotolerant endophytic strains were determined. Both strains were found to possess multiple plant growth promoting activities such as P-solubilization and phytohormone production traits. Osmotic stress had a beneficial effect on Psolubilization, Indole acitic acid and exopolysaccharides production ability of both of the cultures. Osmotic stress had an inhibitory effect on GA production ability of both the cultures. During plant-endophyte association, in vitro conditions, there was an associated decrease in ethylene production by the plant under osmotic stress conditions while IAA, GA and exopolysaccharide production during the plant-endophyte association was significantly enhanced under severe water stress conditions. On the basis of growth at higher PEG concentration, seed germination percentage, plant growth promoting traits and exopolysaccharide production two most promising strains were identified, which can be used as biofertilizers to improve productivity of Cluster bean in arid and semi arid regions of the country. Top Keywords Osmotic stress, Endophytic bacteria, IAA production, GA production, PEG 6000, Exo-polysaccharide, Bacillus sp, B. aryabhatti. Top |