Seed priming with Brassinosteroids alleviates Aluminum toxicity in rice via improving antioxidant defense system and suppressing aluminum uptake

Abstract

\n Brassinosteroids (BRs) are growth-promoting hormones that exhibit high biological activities inside numerous plant species. BRs play a protective role in plants against various stresses. In the present study, seed priming of 24-epibrassinolide (0.01µM) was used to demonstrate the mitigation effect of Aluminum (400µM) in rice plants. BRs application was found effective in control beside plants under aluminum (Al) toxicity. It enhanced seed germination energy, germination percentage as well as root length, shoots length, fresh and dry weight as well under the stressed condition as well as inside control (primed with BRs). Although, Aluminum toxicity induced reduction in seed growth parameters, also in photosynthetic pigments, increased MDA content, and H2O2 production by enhancing the activities of antioxidative enzymes such as ascorbate peroxidase, catalase, and peroxidase in both roots and shoots. These changes were noticed higher inside tolerant variety (YLY-689) as compared to sensitive cultivar (CY-927). Interestingly, 24-EBL copped the stress through decreasing MDA content as well as H2O2 production by more stimulating antioxidant activities to modulate the stress condition under Al stress. Gene expression analysis of SOD-Cu-Zn, SOD-Fe, CATa, CATb, APX02, and APX08 also supported the data related to antioxidant activities. These findings led us toward the conclusion that more induction of antioxidant activities with effective response toward other seed growth parameters with low uptake of Aluminum under 400µM Aluminum stress, 24-EBL was responsible for the mitigation of aluminum stress in rice seedlings.