Enhancing salt stress tolerance in wheat (Triticum aestivum) seedlings: insights from trehalose and mannitol

Abstract

Salinity stress, an ever-present challenge in agriculture and environmental sciences, poses a formidable hurdle for plant growth and productivity in saline-prone regions worldwide. Therefore, this study aimed to explore the effectiveness of trehalose and mannitol induce salt resistance in wheat seedlings. Wheat grains of the commercial variety Sakha 94 were divided into three groups : a group that was pre-soaked in 10 mM trehalose, another group was soaked in 10 mM mannitol, and the last was soaked in distilled water for 1 hour, then the pre soaked grains cultivated in sandy soil, each treatment was divided into two groups, one of which was irrigated with 150 mM NaCl and the other was irrigated with tap water. The results showed that phenols content in wheat seedlings increased and flavonoids reduced due to salt stress. Trehalose and mannitol cause slight increase in total phenols content while total flavonoids were elevated highy in salt-stressed seedlings. Furthermore, Trehalose or mannitol reduced salt-induced lipid peroxidation. Salt stress increases antioxidant enzyme activities of guaiacol peroxidase (G-POX), ascorbate peroxidase (APX), and catalase (CAT) in wheat seedlings, while polyphenol oxidase (PPO) unchanged. Trehalose and mannitol treatments caused an increase in APX, and CAT activities, whereas G-POX not altered but PPO activity were decreased under salt stress conditions. Molecular docking confirmed the interaction of Trehalose or mannitol with peroxidase and ascorbic peroxidase enzymes. Phenyl alanine ammonia layase (PAL) activity was increased in salt-stressed seedlings. We can conclude that pre-soaking of wheat grains in 10 mM trehalose or mannitol improves salinity stress tolerance by enhancing antioxidant defense enzyme and/or phenol biosynthesis, with docking identifying interactions with G-POX, CAT, APX, and PPO.

Keywords: Antioxidant enzymes; Mannitol; Salt stress; Trehalose; Wheat (Triticum estivium).

Fig. 1

Effect of wheat grain pre-soaking in 10 mM trehalose and mannitol on amino acids, proline, total soluble sugar, reducing sugar and protein content in wheat seedlings grown salty condition

Fig. 2

Effect of wheat grain pre-soaking in 10 mM trehalose and mannitol on total phenols and flavonoids contents in wheat seedlings grown under salt stress condition.

Fig. 3

Effect of wheat grain pre-soaking in 10 mM trehalose and mannitol on MDA contents in wheat seedlings grown under salt stress condition

Fig. 4

Effect of wheat grain pre-soaking in 10 mM trehalose and mannitol on antioxidant enzymes (A) guaiacol peroxidase (G-POX), B ascorbate peroxidase (APX), C catalase (CAT), and PPO activities in wheat seedlings grown under salt stress condition

Fig. 5

Interaction between ligands; A trehalose with APX, B mannitol with APX, C trehalose with G-POX, D mannitol with G-POX, Residues with polar interaction with ligands in purple, ligands in green and hydrogen bonds in yellow dashes.

Fig. 6

Catalytic site of PPO, residues in purple, Cu atoms in orange and oxygen atoms in red

Fig. 7

Effect of wheat grain pre-soaking in 10 mM trehalose and mannitol on Phenylalanine ammonia layase activity in wheat seedlings grown under salt stress condition.

Fig. 8

Illustration diagram summarized the effects of Trehalose and mannitol on salt- stress tolerance in wheat seedlings by mitigating the negative effects of ROS through changes of its composition from some metabolites.