Physiological and transcriptional response of carbohydrate and nitrogen metabolism in tomato plant leaves to nickel ion and nitrogen levels

This study investigated how nickel ion (Ni2+) improves carbohydrate and nitrogen (N) metabolism in tomato plant leaves under different N supply levels. We exposed the tomato plants to two levels of N (7.66 and 0.383 mmol center dot L-1) and two levels of Ni2+ (0 and 0.1 mg center dot L-1 NiSO4) under hydroponic conditions. After nine days of treatments, we harvested the leaves for physiological, biochemical, and transcriptome sequencing analysis. Low N (LN) levels reduced the concentration of total N and the activities of enzymes; however, Ni2+ can regulate these levels. Leaf transcriptome analysis identified 3277 differentially expressed genes (DEGs). The DEGs asso-ciated with the glycolytic pathway-tricarboxylic acid (EMP pathway-TCA) cycle, biosynthesis of amino acids, and N metabolism were downregulated after low N application, whereas those regulated by Ni2+ showed high transcript abundances. This study provides valuable insights into the carbohydrate and N metabolism mechanism of tomato plant leaves in response to Ni2+ and N levels.

Automated summary

This study found that nickel ion can regulate the carbohydrate and nitrogen metabolism of tomato plant leaves, especially under low nitrogen supply. Transcriptome analysis of the leaves revealed that genes associated with nitrogen metabolism were downregulated under low nitrogen conditions, while those regulated by nickel ion showed high transcript abundances.