Sugarbeet roots respond to injury with rapid, intense upregulation of glycolytic and fermentative genes and enzymatic activities

Authors: Fugate, Karen; MORIN, MERCEDES - North Dakota State University; Eide, John; FINGER, FERNANDO - Universidade Federal De Vicosa

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/30/2025
Publication Date: 7/1/2025
Citation: Fugate, K.K., Morin, M., Eide, J.D., Finger, F. 2025. Sugarbeet roots respond to injury with rapid, intense upregulation of glycolytic and fermentative genes and enzymatic activities. Scientific Reports. 15.Article 420459. https://doi.org/10.1038/s41598-025-05186-8.
DOI: https://doi.org/10.1038/s41598-025-05186-8

Interpretive Summary: The mechanical operations used to harvest and pile sugarbeet roots inflict cuts, abrasions, bruises and cracks to roots. The healing of root injuries is critical for successful root storage since wound sites allow pathogens to enter and water to be lost from the root which leads to root diseases and dehydration during storage. Following injury, roots initiate a series of reactions to repair wound sites and defend the root against pathogens. These reactions generate new compounds that seal off wound sites and have antimicrobial properties, but utilize sucrose as the starting material for these new compounds. How injured sugarbeet roots marshal sucrose into the building blocks needed for wound healing processes is presently unknown. This information, however, is important for understanding the mechanisms of wound healing and sucrose loss in harvested roots as well as for understanding and optimizing the relationship between wound-healing and sucrose loss. Research, therefore, was conducted to identify changes in the proteins used by sugarbeets to transform sucrose into the biosynthetic building blocks used to repair and defend injured roots. The research identified 34 proteins that were elevated by injury and participate in the conversion of sucrose to other compounds that are needed for wound healing processes. Most of these proteins were members of two primary metabolic pathways in plants, i.e., glycolysis and fermentation. These pathways, therefore, are believed to be of central importance for the repair and defense of injured sugarbeet roots, but also contribute to the sucrose loss that accompanies wound-healing.

Technical Abstract: Mechanical harvesting and piling operations severely wound sugarbeet roots prior to storage which requires rapid healing of injuries to minimize storage losses. Although upregulation of the metabolic enzymes and pathways that provide carbon substrates needed to repair and protect wounded tissues is critically important for efficient wound healing, no information is available regarding how sugarbeet root primary carbon metabolism is altered by injury. Research, therefore, was conducted to identify changes in the expression of genes within primary carbon metabolic pathways that occurred in the 24 h following wounding and characterize wound effects on enzymatic activities for those genes identified as possible effectors of carbon substrate availability. Root injury altered expression of 34 genes involved in primary carbon metabolism including three genes involved in sucrose catabolism, 17 glycolytic genes, three genes contributing to the tricarboxylic acid (TCA) cycle and organic acid metabolism, and nine genes involved in fermentation. A total of 28 genes were upregulated by wounding, with genes contributing to sucrose catabolism, glycolysis, and fermentation, but not the TCA cycle, highly upregulated. Enzymatic activities for the protein products of highly upregulated genes that were part of glycolytic and fermentation pathways were significantly elevated in wounded roots, while enzyme activities for the protein products of sucrolytic genes were generally unaffected by root injury. These results indicate that injured sugarbeet roots generate the carbon substrates required for wound-healing processes by rapidly and intensely upregulating glycolytic and fermentative pathways, with minimal alteration in sucrose catabolizing activity or TCA cycle gene expression. Overall, this study indicates a dominant role for glycolysis in the control and upregulation of carbon metabolism to support wound healing in postharvest sugarbeet roots that is not dependent on elevations in sucrose catabolism or the TCA cycle. The central importance of glycolysis to wound healing is additionally supported by the intense upregulation of fermentation, that functions as a mechanism to maintain glycolytic flux when the TCA cycle is insufficiently able to metabolize the end-products of glycolysis.