Elucidating the effect of growth promoting endophytic fungus Piriformospora indica for seedling stage salinity tolerance in contrasting rice genotypes

The growth and productivity of rice ( Oryza sativa L.) have been hampered by high soil salinity. Microbial endophytes, the most significant soil microorganisms, boost plant output per unit area by changing physiologically, and ecologically, allowing crop development in saline soils or climates with biotic and abiotic stresses. Piriformospora indica , an endophytic fungus, promotes plant development while also increasing plant resilience to environmental stresses such as salinity. Here, we analyzed the beneficial effect of P. indica association on rice seedlings of both tolerant variety VTL-6 and susceptible variety Manu Ratna during different levels of salinity stress conditions (0, 100, 150, 200, 300 and 500 mM NaCl), to check the highest tolerating levels of salinity stress by P . indica in selected tolerant and susceptible rice genotypes. The growth parameters of rice seedlings such as shoot and root lengths, fresh and dry weights, seedling vigor index 1 and 2, root volume and root shoot ratio were found to be enhanced in P. indica -inoculated rice seedlings as compared to non-inoculated control seedlings, irrespective of whether they are exposed to salt stress or not. In the presence of the fungus, however, salt-stressed seedlings performed significantly better than non-inoculated control seedlings by maintain low Na + /K + ratio. All the growth parameters were decreased as the increase in salinity levels. The findings of this study revealed that this fungus has an important function in improving rice development under salt stress environments.