Galactinol synthase 4 influences plant height by affecting phenylpropanoid metabolism and the balance of soluble carbohydrates in tomato.

Plant height is a key trait that significantly influences plant architecture, disease resistance, adaptability to mechanical cultivation, and overall economic yield. Galactinol synthase (GolS) is a crucial enzyme involved in the biosynthesis of raffinose family oligosaccharides (RFOs). It plays a significant role in carbohydrate transport and storage, combating abiotic and biotic stresses, and regulating plant growth and development. The present study employed CRISPR/Cas9 gene-editing technology to create the gols4 mutant in tomato (Solanum lycopersicum), which exhibits a semi-dwarf phenotype. Results showed that glucose, sucrose, myo-inositol, galactinol, and raffinose levels were significantly reduced in the slgols4 mutant, impairing material transport and affecting the balance of soluble carbohydrates. Integration of transcriptomics and metabolomics data indicated not only a decrease in the expression of synthesis genes related to phenylpropanoid biosynthesis but also a significant reduction in the content of lignin and flavonoids, which are byproducts of phenylpropanoid metabolism. This may be a key factor contributing to dwarfism. Overall, these findings provide evidence for the role of SlGolS4 in regulating sugar metabolism and phenylpropanoid metabolism, offering new insights into tomato dwarfing cultivation and germplasm resources.