Involvement of Nitric Oxide in Implementation of a Protective Effect of Epicastasterone and Its Monosalicylate on Wheat Seedlings under Heat Stress

• Published in: Applied biochemistry and microbiology Vol. 58; no. 4; pp. 368 - 374
• Main Authors: Litvinovskaya, R. P., Shkliarevskyi, M. A., Kolupaev, Yu. E., Kokorev, A. I., Khripach, V. A.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01-08-2022; Springer Nature B.V
• Subjects: Antagonists; Biochemistry; Biomedical and Life Sciences; Brassinosteroids; Heat stress; Heat tolerance; Hydrogen peroxide; Inhibitors; Life Sciences; Medical Microbiology; Microbiology; Nitrate reductase; Nitric oxide; Nitric-oxide synthase; Reductases; Roots; Salicylic acid; Seedlings; Sodium tungstate; Wheat; 24-epicastasterone 2-monosalicylate; heat tolerance; nitric oxide; 24-epicastasterone; brassinosteroids; reactive oxygen species; nitrate reductase
• ISSN: 0003-6838; 1608-3024
• DOI: 10.1134/S000368382204010X

We examined the involvement of nitric oxide (NO) in the protective effect of 24-epicastasterone (EC) and its conjugate with a salicylic acid residue (EC 2-monosalicylate, ECMS) on etiolated wheat seedlings under heat stress. The effect of EC and ECMS at 50 nM concentration, which increased the seedling survival after deleterious heating, led to a transient increase in the NO content in roots. The seedling treatment with NO scavenger PTIO (2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) completely prevented the stress–protective effect of EC and reduced the protective effect of ECMS. The increase in the content of NO caused by the action of EC and ECMS was noticeably leveled, it may simply be less pronounced in the presence of the sodium tungstate nitrate reductase inhibitor, but not the NO synthase inhibitor aminoguanidine. The increase in the NO content induced by both studied brassinosteroids did not occur when seedlings were treated with a hydrogen peroxide (H
2
O
2
) scavenger, dimethylthiourea. The seedling treatment with NO antagonists had practically no effect on the increase of the H
2
O
2
content in roots caused by EC but it decreased this effect of ECMS. It is supposed that the increase of NO content can occur due to the increase of the H
2
O
2
level in the signal pathway induced by EC. The ECMS-induced interactions between NO and H
2
O
2
as signaling mediators can be more complex. The results suggest that NO is involved in the implementation of the EC and ECMS protective effect on seedlings under heat stress.