Stress Mitigation of Salinity-Induced Growth Inhibition In Mungbean Through Association With the Endophytic Fungus Stemphylium solani

Abstract

The purpose of this research was to assess the behavior of the endophytic fungus (Stemphylium solani) in conferring salt tolerance in mung bean, with respect to alterations in the plant's ionomic balance, fluctuations in endogenous IAA concentration, antioxidant enzyme activities, physiological and biochemical attributes, and overall seedling growth performance. A completely randomized pot experiment was conducted to assess the effect of the endophytic fungus Stemphylium solani on mung bean seedlings grown under control and salinity (150 mM NaCl) conditions. After 35 days of treatment, plant growth, physiological, biochemical, antioxidant, and ionic characteristics were evaluated. Analysis of the data revealed that salinity reduced seedling growth (plant height, root length, number of leaves, fresh biomass, and dry biomass), photosynthetic pigments (chlorophyll a, chlorophyll b, and total chlorophyll), endogenous IAA, total carbohydrates, total proteins, total lipids, and essential mineral nutrients (K, Ca, Mg, N, and P). On the other hand, salinity increased chlorophyll a/b ratio, phenols, tannins, flavonoids, proline, lipid peroxidation, antioxidant enzyme activities (ascorbate peroxidase and catalase), Na and Cl accumulation, and Na/K and Na/Ca ratios. In this study, the endophytic fungus exhibited promising growth promoting activity under both normal and saline conditions. The results showed that Stemphylium solani improved plant growth, biomass, chlorophyll contents, total carbohydrates, total proteins, flavonoids, antioxidant enzyme activities, endogenous IAA, and the uptake of K, Ca, Mg, N, and P, while reducing lipid peroxidation, phenols, tannins, Na and Cl accumulation, and Na/K and Na/Ca ratios under salinity stress. The present study concludes that the association of Stemphylium solani confers salt tolerance in mung bean and suggests its potential use as a bioinoculant for improving crop productivity under saline environments of Khyber Pakhtunkhwa (KPK).