A phytobeneficial strain Planomicrobium sp. MSSA-10 triggered oxidative stress responsive mechanisms and regulated the growth of pea plants under induced saline environment.

AIMS: The study was planned to characterize Planomicrobium sp. MSSA-10 for plant-beneficial traits and to evaluate its inoculation impact on physiology of pea plants under different salinity levels. METHODS AND RESULTS: Strain MSSA-10 was isolated from pea rhizosphere and identified by the analysis of 16S rRNA gene sequence. The strain demonstrated phosphate solubilization and auxin production up to 2 mol l-1 NaCl and exhibited 1-aminocyclopropane-1-carboxylic acid deaminase activity up to 1·5 mol l-1 salt. In an inoculation experiment under different salinity regimes, a significant increase in growth was observed associated with decreased levels of reactive oxygen species and enhanced antioxidative enzyme activities. The strain also promoted the translocation of nutrients in plants with subsequent increase in chlorophyll and protein contents as compared to noninoculated plants. It has been observed that rifampicin-resistant derivatives of MSSA-10 were able to survive for 30 days at optimum cell density with pea rhizosphere. CONCLUSION: Growth-stimulating effect of MSSA-10 on pea plants may be attributed to its rhizosphere competence, nutrient mobilization and modulation of plant oxidative damage repair mechanisms under saline environment. SIGNIFICANCE AND IMPACT OF THE STUDY: Planomicrobium sp. MSSA-10 might be used as potent bioinoculant to relieve pea plants from deleterious effects of salinity.