Characterization of Bacterial Endophyte Imparting Drought Tolerance in Rice (Oryza sativa L.).

Drought is a major abiotic stress which affects plant growth and productivity. It is proven in recent years, that microorganisms (fungi and bacteria) which can symbiotically inhabit the plant system and impart tolerance against abiotic stresses. In the present study, 58 bacterial endophytes isolated from Himalayan cold deserts were screened in-vitro using Polyethylene glycol (PEG MW-8000) against drought tolerance at different concentrations (5%, 10%, 15%, 20%, 25%). Out of 58 isolates, 8 isolates showed drought tolerance up to 20 per cent PEG. The drought tolerance of sensitive crops like, Rice (var. IR-64) seedlings were standardized by paper towel method using pre-germinated seeds. Further, pre-germinated seeds of rice seedings inoculated with the eight-drought tolerant endophytic bacteria were grown at 14.3 per cent PEG in paper towel method, of which one endophyte (CBE 11) significantly showed increased seedling length compared to uninoculated seeds. The endophyte was identified as Stenotrophomonas maltophilia by 16S rRNA gene sequence. It was found that this bacterial endophyte can impart drought tolerance in rice. [ABSTRACT FROM AUTHOR]