Biological elicitors to enhance wound healing responses in cut potato tubers

Abstract

Wounding-induced postharvest losses of potato tubers is a serious economic problem in the United States (≥$320 million year−1) and globally. Developing safe and effective postharvest treatment strategy to enhance wound-healing (WH) responses is extremely important to mitigate wound-induced potato tuber losses. Formation of protective suberin layer in the wound surface is the primary WH response of potato tubers. In this study, biological elicitor based postharvest treatment strategy using water-soluble chitosan oligosaccharide (COS 0.125 g L−1), and phenolics-rich cranberry pomace (Nutricran 0.125 g L−1) was employed to accelerate formation of suberin layer in wounded potato tubers. A standardized disk model system was used to study WH responses in certified mini tubers of cv. Russet Burbank and cv. Russet Norkotah, 4 days after wounding. The effects of these elicitor treatments on the regulation of pentose phosphate pathway (PPP) and associated antioxidant enzyme responses were investigated as key control points for improving suberization and related WH processes in wounded potato tubers. Postharvest treatments of COS and Nutricran resulted in improved accumulation of suberin polyphenolics (SPP) in wounded tissues of both potato cultivars after 4 days of WH when compared to control (buffer treatment). Additionally, higher soluble phenolic content, enhanced activity of glucose-6-phosphate dehydrogenase (G6PDH), guaiacol peroxidase (GPX), and catalase (CAT) were observed in COS-treated tissues of cv. Russet Burbank. Therefore, COS postharvest treatment can be integrated and optimized in further investigations to potentially improve suberization and WH processes in wounded potato tubers.