The effect of endophytic and rhizospheric bacteria was studied on salt stress in a local paddy rice (Oryza sativa L.) variety GJ-17. Plants inoculated with endophytic bacterium Pseudomonas pseudoalcaligenes showed significantly higher concentration of glycine betaine-like quaternary compounds and higher shoot biomass at lower salinity levels. While at higher salinity levels, mixture of both P. pseudoalcaligenes and Bacillus pumilus showed better response against the adverse effects of salinity. However, accumulation of proline showed an opposite trend against plant growth promoting rhizobacteria (PGPR) treatment in salinity stress. Proline concentration increased with salinity but decreased in plants inoculated with either of the PGPRs or mixture of both P. pseudoalcaligenes and B. pumilus. The present study shows that inoculation of paddy rice (Oryza sativa L.) with a mixture of endophytic and rhizospheric bacteria could serve as a useful tool for alleviating salinity stress.

The response of two root associated bacteria Pseudomonas pseudoalcaligenes and Bacillus pumilus were studied in the (salt-sensitive) rice GJ17 cultivar to salinity under controlled environmental growth conditions for protection of plant from adverse effect of salinity. Salinity affects the growth of salt-sensitive cultivar, but inoculation of plant growth promoting rhizobacteria (PGPR) reduces the harmful effect of salinity. The present study states that PGPR helps to reduce lipid peroxidation and superoxide dismutase activity in salt-sensitive GJ17 cultivar under salinity and play an important role in the growth regulation for positive adaptation of plants to salt stress. This study shows that inoculation of paddy (Oryza sativa) with such bacteria could provide salt-tolerant ability by reducing the toxicity of reactive oxygen species by reducing plant cell membrane index, cell caspase-like protease activity, and programmed cell death and hence resulted in increase cell viability. As these isolates remain associated with the roots, the effects of tolerance against salinity are observed here. Results also indicate that isolated PGPR strain help in alleviating up to 1.5 % salinity stress as well as improve tolerance.

The possible role of plant growth-promoting rhizobacteria (PGPR) to alleviate salt stress during plant growth has been studied on paddy rice (Oryza sativa L.) 'GJ-17' under greenhouse conditions; the study included growth parameters, mineral concentration, and antioxidant enzyme level. Salinity reduced plant growth, but PGPR inoculation reduced its harmful effect up to 1% salinity. Plants inoculated with PGPR under saline conditions showed 16% higher germination, 8% higher survival, 27% higher dry weight, and 31% higher plant height. Similarly, PGPR inoculated plants showed increased concentrations of N(26%), P (16%), K (31%), and reduced concentrations of Na (71%) and Ca (36%) as compared to non-inoculated control plants under saline conditions. Plants inoculated with PGPR under saline conditions also showed significant variations in antioxidant levels and growth physiology. Results suggested that inoculation with PGPR Bacillus pumilus and Pseudomonas pseudoalcaligenes in salt-stressed plants could help to alleviate salt stress in the paddy.

Tomato early blight occurs worldwide and it is prevalent wherever tomatoes are grown. Alternaria solani Sorauer, the causal agent, has been recognized as a serious foliar pathogen of tomato and there are very few cultivars which possess resistance against early blight. Alternaric acid is the major toxin of A. solani. In this study, alternaric acid and fungal culture filtrate were used as an elicitor in NDT-96 (tolerant) and GP-5 (susceptible) tomato varieties in order to study and compare their abilities to induce defense-related enzymes, viz., catalase, peroxidase, β-1,3 glucanase, phenylalanineammonia-lyase (PAL), chitinase and polyphenoloxidase (PPO) along with total phenols, and total soluble proteins. NDT-96 showed a rapid induction of all these pathogenesis-related enzymes except catalase along with total phenols as compared to GP-5 with both the treatments. Differential expression of total soluble proteins revealed higher protein content in NDT-96 as compared with GP-5. A 49.48 kDa protein was observed to be absent in GP-5. In addition, 25 microsatellite markers (SSR) were screened for polymorphisms among the above mentioned two tomato varieties. Of these, SSR 286 revealed a significant polymorphic band of 108 bp in NDT-96.

No abstract