Bacterial mediated amelioration of drought stress in drought tolerant and susceptible cultivars of rice (Oryza sativa L.)

In the present study, plant growth promoting rhizobacterial (PGPR) strains Pseudomonas fluorescence strain P2, Pseudomonas jessenii R62,  Pseudomonas synxantha R81, Bacillus cereus BSB 38 (14B), Arthrobacter nitroguajacolicus strainYB3 and strain YB5 were tested for their role in enhancing plant growth and induction of stress related enzymes in  Sahbhagi (drought tolerance) and IR-64 (drought sensitive) cultivars of rice (Oryza sativa L.) under different level of drought stress. PGPRs, P. jessenii, R62, P. synxantha, R81 were used as one consortium similarly A.  nitroguajacolicus strainYB3 and strain YB5 were used as other consortia. Most of the PGPR inoculated plants showed enhanced growth as compared to uninoculated plants under all the level of drought stress. Quantitative analyses of antioxidant enzymes indicated that majority of the PGPRs inoculated plants in both varieties showed higher proline content, higher activity of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX) and lower level of hydrogen peroxide (H2O2), malondialdehyde (MDA) in leaves at all the level of drought stress. The study suggests that PGPRs alleviates oxidative damage in rice plants grown under drought by improving plant growth and activating antioxidant defense systems, thereby improving stability of membranes in plant cells. This study provides evidence for a beneficial effect of PGPRs application in enhancing drought tolerance of rice under water deficit conditions. Key words: Plant growth promoting rhizobacterial (PGPR), plant growth promotion, drought stress, antioxidant, rice

Bacterial Diversity in Cold Environments of Indian Himalayas

Not AvailableThe remote cold environments of Indian Himalayas are witnessed by extreme situations with a lot of variations in temperatures, low availability of water and nutrients and exposure to a lot of radiations. These extreme environments generally considered unfavourable to growth and survival of plants and animals are usually colonized by the microorganisms capable of growth and survivability under the prevailing severe conditions. Because of the extremophilic enzymes, proteins and biomolecules possessed by cold-adapted microorganism, they are of importance for industry, agriculture and biotechnology. In this chapter, (1) diversity of bacteria present in cold environments based on culturing and metagenomics approaches, (2) microorganisms from cold environments in agriculture, (3) novel bacteria from cold environments and (4) genome sequencing of bacteria from cold environments have been discussed. Bacteria affiliated to various phyla like Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, Acidobacteria, Gemmatimonadetes, Planctomycetes, Chlamydiae, Chlorobi, Chloroflexi, Dictyoglomi, Fibrobacteres, Nitrospirae and Verrucomicrobia have been reported from the Indian Himalayas. Microorganisms belonging to various genera for improving agriculture production under cold environment have been isolated and identified. Twenty-one novel species of bacteria have been isolated from different locations in the cold environments of the Himalayas. A genome of 18 strains isolated from these cold environments has been sequenced and published.Not Availabl