Evaluation of comparative effects of arbuscular mycorrhiza (Rhizophagus intraradices) and endophyte (Piriformospora indica) association with finger millet (Eleusine coracana) under drought stress

- The differential influence of arbuscular mycorrhiza (Ri) and endophyte (Pi) on drought tolerance in finger millet was found.
- Chlorophyll and relative water content significantly increased in Pi inoculated plants.
- Ri was more effective in reducing the electrolyte leakages and hydrogen peroxide content under drought.
- Both the fungi variably enhanced the activities of antioxidant enzymes resulting in less drought induced lipid peroxidation.

The differential influence of arbuscular mycorrhiza- Rhizophagus intraradices (Ri) and endophyte- Piriformospora indica (Pi) on drought tolerance in finger millet was studied. The seedlings were grown with and without symbiotic association under three different water regimes and the effect of association on physiological and biochemical traits related to stress tolerance were recorded. The treated plants exhibited an enhanced seedlings growth under drought, while Ri seedlings had greater plant biomass as compared to endophytic fungi. Chlorophyll and relative water content were significantly increased in Pi inoculated plants. Ri was more effective in reducing the electrolyte leakages, malondialdehyde (MDA) and hydrogen peroxide (H2O2) content as compare to control and Pi treatments. Proline content in leaves increased significantly with Ri and Pi, but Ri treated plants accumulated more total soluble sugars as compared to inoculated seedlings. In case of secondary metabolites, phenols accumulation was influenced by both Ri and Pi under water stress, while more flavonoids were present in Ri seedlings. Also Pi showed better performance with respect to improved Ascorbate-glutathione redox status under mild and severe stress. Both symbionts differentially enhanced the activities of the antioxidant enzymes resulting in upto 25% reduction in drought-induced lipid peroxidation. Obtained results indicated that, inoculation with both fungi helped finger millet seedlings in drought tolerance through a stronger antioxidant defence system, higher chlorophyll content, and an enriched osmoregulatory network. Both Ri and Pi fungi may differ in their biochemical and genetic mechanisms behind the interaction; however can improve the growth of finger millet in drought-affected soils.