Azolla filiculoides extract improved salt tolerance in wheat (Triticum aestivum L.) is associated with prompting osmostasis, antioxidant potential and stress‑interrelated genes

Abstract

The growth and productivity of crop plants are negatively affected by salinity‑induced ionic and oxidative stresses. This study aimed to provide insight into the interaction between NaCl‑induced salinity and Azolla aqueous extract (AAE) on growth, antioxidant balance, and stress‑responsive gene expression in wheat seedlings. In a pot experiment, wheat kernels were primed for 21 h with either deionized water or 0.1% AAE. Water‑primed seedlings received either tap water, 250 mM NaCl, AAE spray, or AAE spray + NaCl. The AAE‑primed seedlings received either tap water or 250 mM NaCl. Salinity lowered growth rate, chlorophyll level, and protein and amino acids pool. However, carotenoids, stress indicators (EL, MDA, and H2O2), osmomodulators (sugars, and proline), antioxidant enzymes (CAT, POD, APX, and PPO), and the expression of some stress‑responsive genes (POD, PPO and PAL, PCS, and TLP) were significantly increased. However, administering AAE contributed to increased growth, balanced leaf pigments and assimilation efficacy, diminished stress indicators, rebalanced osmomodulators and antioxidant enzymes, and down‑regulation of stress‑induced genes in NaCl‑stressed plants, with priming surpassing spray in most cases. In conclusion, AAE can be used as a green approach to sustain regular growth and metabolism and to remodel the physicochemical status of wheat seedlings thriving in salt‑affected soils.