Frankia: A Promising N-Fixing Plant Growth Promoting Rhizobacteria (PGPR) Improved Drought Tolerance in Crops at Higher Altitude

The high-altitude Himalayan regions are unique micro-climatic and geographic separations that have precise agro-technical needs, which is quite different from other agro-climacteric zones of India for vegetable production. In such marginal degraded regions mainly drought stress causes significant harmful effect on survival, biomass production and yields of vegetable crops up to 70%. Since drought tolerance is quantitative and multigenic in nature, a massive challenge exists to solve this problem. The use of N-fixing growth promoting rhizobacteria (PGPR) in place of agrochemicals (pesticides and fertilizers) is a promising approach to increase the plant productivity by naturally increasing nitrogen content of soil and also not leads to deterioration of the soil micro-flora and environment. In this attempt, this chapter highlights the importance of promising indigenous Frankia sp. strains (potential N-fixing PGPR) isolated from the root nodules of Casuarina plant of Kumaon region of Uttarakhand, India. Also, the effect of bio-inoculation of isolated Frankia sp. strains has been demonstrated to improve PEG-mediated drought stress tolerance in tomato (Solanum lycopersicum L. cv. Pusa ruby) for improving sustainable hill agriculture in rain fed conditions. This successful model may be useful for improving the productivity of other crops grown in drought prone regions of Himalaya.