| Abstrakt: |
Salt stress adversely affects the growth and development of plants. However, plants counteract such stress with different mechanisms to some extent. Symbiotic association of bacterial endophytes alleviate the abiotic stress and promote the growth of plant. In this study, 58 bacterial endophytes isolated from Himalayan cold desert plants were screened in-vitro at different concentrations (0.5M, 1.0M, 1.5M, 2.0M, 2.5M) of NaCl. Out of 58 isolates, 9 isolates designated as PBE 4, PBE 6, PBE 8, PBE 15, CBE 12, NBE 7, NBE 20, NBE 21, NBE 23 showed salt tolerance up to 2.0 M NaCl. Nine bacterial isolates inoculated to pre-germinated rice (var. IR 64) seeds and grown on paper towel treated with 150 mM NaCl (based on LC50value) only two endophytes (PBE 8 and NBE 7) significantly increased the seedling length compared to unino culated seedlings. The two isolates were identified as Enterobacter hormaechei and Pseudomonas fluorescens using 16S rRNA gene sequence. These two bacterial isolates also showed production of growth promoting traits such as nitrogen fixation, phosphate solubilization, production of HCN, NH3, siderophore, proline, IAA, gibberellic acid, abscisic acid and salicylic acid. Further, inoculation of these bacteria (Enterobacter hormaechei and Pseudomonas fluorescens) to pre germinated rice seeds significantly increased the plant growth at 4 dS m-1 NaCl stress under greenhouse conditions. This study suggested that endophytic isolates Enterobacter hormaechei and Pseudomonas fluorescens impart salinity stress tolerance and promote growth of rice seedlings. [ABSTRACT FROM AUTHOR] |
