The Role of Peroxidase in Suberin Assembly in Potato

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2026-01-21

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Abstract

Suberin is a complex heteropolymer that forms an apoplastic diffusion barrier in plant tissues, protecting against water loss and pathogen invasion. In potato tubers (Solanum tuberosum), suberization is a key wound-healing response that requires coordinated deposition of phenolic and aliphatic monomers. Although suberin biosynthesis has been studied extensively, the specific roles of individual class III peroxidases (PRXs) in catalyzing oxidative polymerization of phenolic monomers remain unclear. Here, we examined the functional contributions of three wound-inducible peroxidase genes—PRX19, PRX55, and PRX105—using RNA interference (RNAi) knockdown to dissect isoform-specific roles in suberin assembly and barrier formation. Transcript analyses confirmed strong (>80%) silencing of each target gene, yet physiological and biochemical consequences varied substantially. PRX19-RNAi tubers showed sharply reduced total peroxidase activity, substantial loss of phenolic suberin, disrupted lamellar ultrastructure, and impaired water-retention capacity. Metabolic profiling revealed altered accumulation of soluble phenolics and defective incorporation of aliphatic monomers, indicating that PRX19 is required to generate phenolic radicals that form the initial poly(phenolic) scaffold necessary for subsequent aliphatic deposition. By contrast, PRX55- and PRX105-RNAi lines displayed only modest or negligible effects on peroxidase activity, suberin chemistry, and barrier integrity, suggesting partial redundancy or supporting roles during wound healing. Together, these findings support a model in which PRX19 acts as a central catalytic hub in early suberin assembly, governing phenolic coupling and lamellar organization. This work advances understanding of the enzymatic and metabolic coordination underlying wound-induced suberization and highlights PRX19 as a potential molecular target for improving postharvest tuber quality, stress tolerance, and disease resistance through targeted modulation of peroxidase activity.

Summary for Lay Audience

Potatoes are an essential food crop worldwide, but they are susceptible to damage and decay after harvest. When a potato tuber is injured by handling, harvesting, or pests, it initiates a natural wound-healing process that forms a protective barrier called suberin. Suberin is a complex, waxy layer that acts like a natural shield, preventing water loss and blocking infections from bacteria and fungi. Understanding how this barrier forms is crucial for improving storage and reducing food waste. In my research, I focused on a protein called Class III peroxidase PRX19, which plays a central role in building this protective layer. Using advanced techniques, including transmission electron microscopy, we could visualize the microscopic lamellae (the layered structure of suberin) that form during wound healing. We also used metabolomics to measure the small chemical compounds involved in this process, particularly those linked to phenylpropanoid metabolism, which produces important building blocks for suberin. My results show that PRX19 helps organize the suberin lamellae and ensures proper chemical bonding of phenolic monomers. Without PRX19, the protective barrier is thinner, less structured, and less effective at preventing damage. This research highlights the sophisticated ways plants protect themselves and adapt to injury. By understanding the molecular and biochemical mechanisms behind wound healing in potatoes, we can develop strategies to improve the storage and shelf-life of this crop. Such improvements could reduce losses during transportation and storage, ensuring that more potatoes reach consumers in good condition. In addition, these findings could inform broader agricultural practices and help scientists develop crops that are more resilient to stress and damage. Overall, my work sheds light on the “healing” process in plants at a detailed molecular level, showing how PRX19 coordinates both structural and chemical aspects of suberin formation. These insights provide a foundation for enhancing crop protection, reducing postharvest losses, and ultimately contributing to food security around the world.

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Keywords

Suberin, Potato tuber, Wound-healing, Class III peroxidase, PRX19, Plant defense, RNA interference, Phenolic monomers, Aliphatic monomers

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https://hdl.handle.net/20.500.14721/39520

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