Involvement of Nitric Oxide and Melatonin Enhances Cadmium Resistance of Tomato Seedlings through Regulation of the Ascorbate-Glutathione Cycle and ROS Metabolism.

Content Provider	Europe PMC
Author	Xu, Junrong Wei, Zhien Lu, Xuefang Liu, Yunzhi Yu, Wenjin Li, Changxia
Editor	Igamberdiev, Abir U. Palma, José M. Liao, Weibiao
Copyright Year	2023
Abstract	Melatonin (MT) and nitric oxide (NO) act as signaling molecules that can enhance cadmium (Cd) stress resistance in plants. However, little information is available about the relationship between MT and NO during seedling growth under Cd stress. We hypothesize that NO may be involved in how MT responds to Cd stress during seedling growth. The aim of this study is to evaluate the relationship and mechanism of response. The results indicate that different concentrations of Cd inhibit the growth of tomato seedlings. Exogenous MT or NO promotes seedling growth under Cd stress, with a maximal biological response at 100 μM MT or NO. The promotive effects of MT-induced seedling growth under Cd stress are suppressed by NO scavenger 2-4-carboxyphenyl-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide (cPTIO), suggesting that NO may be involved in MT-induced seedling growth under Cd stress. MT or NO decreases the content of hydrogen peroxide (H2O2), malonaldehyde (MDA), dehydroascorbic acid (DHA), and oxidized glutathione (GSSG); improves the content of ascorbic acid (AsA) and glutathione (GSH) and the ratios of AsA/DHA and GSH/GSSG; and enhances the activities of glutathione reductase (GR), monodehydroascorbic acid reductase (MDHAR), dehydroascorbic acid reductase (DHAR), ascorbic acid oxidase (AAO), and ascorbate peroxidase (APX) to alleviate oxidative damage. Moreover, the expression of genes associated with the ascorbate-glutathione (AsA-GSH) cycle and reactive oxygen species (ROS) are up-regulated by MT or NO under Cd conditions, including AAO, AAOH, APX1, APX6, DHAR1, DHAR2, MDHAR, and GR. However, NO scavenger cPTIO reverses the positive effects regulated by MT. The results indicate that MT-mediated NO enhances Cd tolerance by regulating AsA-GSH cycle and ROS metabolism.
Journal	International Journal of Molecular Sciences [Int J Mol Sci]
Volume Number	24
DOI	10.3390/ijms24119526
PubMed Central reference number	PMC10253633
Issue Number	11
PubMed reference number	37298477
e-ISSN	14220067
Language	English
Publisher	Molecular Diversity Preservation International (MDPI)
Publisher Date	2023-05-31
Access Restriction	Open
Subject Keyword	nitric oxide melatonin Cd stress AsA-GSH cycle regulator pathway gene expression
Content Type	Text
Resource Type	Article
Subject	Physical and Theoretical Chemistry Molecular Biology Spectroscopy Catalysis Computer Science Applications Medicine Inorganic Chemistry Organic Chemistry