Metabolomics and transcriptomics combined with physiology reveal key metabolic pathway responses in tobacco roots exposed to NaHS

Hydrogen sulfide (H₂S) is a new endogenous gas signaling molecule alongside nitric oxide (NO) and carbon monoxide (CO). In recent years, many studies have shown that it is involved in a variety of physiological activities, promoting root organogenesis, regulating stomatal movement and photosynthesis, and playing an important role in promoting plant growth and development and improving the stress resistance of the plant Plants can play. Tobacco is a special and an important cash crop whose growth usually determines the economic income of farmers. Tobacco root development directly affects leaf growth, disease resistance, chemical composition and yield. However, to date, there are limited studies on the mechanism of H₂S in promoting tobacco growth. In this study, tobacco seedlings were exposed to NaHS (exogenous H₂S donor) at concentrations of 0, 200, 400, 600, and 800 mg/L. With the gradual increase of NaHS concentration, the root length, wet weight, root activity and antioxidant enzymatic activities of CAT (catalase), SOD (superoxide dismutase) and POD (peroxidase) of tobacco roots showed an increasing tendency. The transcriptome and metabolome showed that NaHS mainly affected 162 key genes, 44 key enzymes, and two metabolic pathways (the brassinolide synthesis pathway and the aspartic acid biosynthesis pathway) in tobacco seedlings after treatment with 600 mg/L NaHS. On the one hand, the addition of exogenous NaHS can promote the development of tobacco roots as the basis of tobacco planting. On the other hand, the use of NaHS can reduce the use of pesticides and better protect the ecological environment. In conclusion, this study provides new insights into the main metabolic pathway in the response of tobacco roots to NaHS and new genetic clues for further investigation- of plant root development.