Isolation and Characterization of Drought Tolerant Bacteria from Rice Phyllosphere

Abstract

Tamil Nadu is one of the top rice production states in India. Southwest monsoon failure of recent years in Tamil Nadu hits with severe drought, especially in the regions of Ramanathapuram districts. The main objective of present study is to isolate drought tolerant bacteria from phyllosphere of drought tolerant rice varieties cultivated in paramakudi region. Rice phyllosphere constitutes the diversified microbial community. The phyllosphere bacteria were isolated in different media Nutrient agar, Tryptic soy agar, R2A agar, and King’s B media from four drought tolerant rice varieties Anna R(4), PMK3, Nootripattu and Mattaikar. A total of 50 different bacterial isolates were purified and screened for abiotic stress tolerance such as drought stress at PEG6000 (-0.15MPa, -0.49MPa, -0.73MPa and -1.2MPa), salt stress at 1.2M NaCl and temperature stress at 50oC. The isolates were named with series PB. The best 8 isolates PB3, P17, PB18, PB23, PB24, PB37, PB46 and PB50 was first biochemically characterized and screened for production of plant growth hormones IAA and GA3 at different PEG6000 stress. The result shows PB50 and PB46 has highest production of plant growth hormones and sustain drought stress. Future works are characterization of isolates for Plant growth promotion activities and application of isolates on rice for drought mitigation.