Regulating Function of Exogenous Salicylic Acid on Sugar Metabolism in Tomato Seedlings

Aims: SA (Salicylic acid) is a key regulator for sugar metabolic pathway, but the regulating function on sugar metabolism in tomato seedlings is imperfect. In this study, tomato seedlings were sprayed with SA, and then soluble sugar contents, enzyme related to sugar metabolism levels, gene expressions were determined.

Study Design: In order to analyze the mechanism of SA in sugar metabolic pathway, tomato seedlings were sprayed with SA, and then soluble sugar contents, enzyme related to sugar metabolism levels, gene expressions were determined.

Place and Duration of Study: College of Biological Science and Technology, between December 2021 and May 2022.

Methodology: The expressions of genes related to sugar metabolism in tomato were measured by qRT-PCR. The contents of soluble sugar in tomato seedings were measured with HPLC (High performance liquid chromatography).

Results: The sugar metabolism in tomato seedlings was affected by SA treatment for 6 h. The contents of fructose, glucose and sucrose were improved in tomato seedlings by SA treatment. Between 6 to 24 h, enzymatic activities of SlAI, SlNI and SlSS were higher than those in controls, while there was little change in enzyme activity of SISPS.

Conclusion: The contents of soluble sugar, enzyme activities related to sugar metabolism had changed considerably by SA treatment. Especially from 6 h to 24 h after SA treatment, the contents of fructose and glucose were significantly higher than those of the control group, and the changes of sugar contents were mainly related to the increases of enzyme activities of AI, NI and SS, suggesting that SA treatment mainly affected the activities of SlAI, SlNI and SlSS to promote the accumulations of soluble sugars.