Sprout-suppressing 1,4-dimethylnaphthalene treatment reduces dry rot infection in potato tubers during postharvest storage

Authors: DE SOUSA SANTOS, MIRELLE - Universidade Federal De Vicosa; ARAUJO, NICOLAS - Universidade Federal De Vicosa; DE ARAUJO, FERNANDA - Universidade Federal De Vicosa; DA SILVA, MARIANA - Universidade Federal De Vicosa; PEREIRA, OLINTO - Universidade Federal De Vicosa; Dogramaci, Munevver; FINGER, FERNANDO - Universidade Federal De Vicosa

Submitted to: Postharvest Biology and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/19/2023
Publication Date: 7/31/2023
Citation: De Sousa Santos, M.N., Araujo, N.O., De Araujo, F.F., Da Silva, M.A., Pereira, O.L., Dogramaci, M., Finger, F.L. 2023. Sprout-suppressing 1,4-dimethylnaphthalene treatment reduces dry rot infection in potato tubers during postharvest storage. Postharvest Biology and Technology. https://doi.org/10.1016/j.postharvbio.2023.112485.
DOI: https://doi.org/10.1016/j.postharvbio.2023.112485

Interpretive Summary: Postharvest deterioration of potato due to disease and/or physiological processes cause significant crop losses during storage. Dry rot is a major postharvest disease caused by a fungal pathogen. Dry rot typically develops on cut and bruised tubers, which ultimately facilitates entrance into the tuber where rotting can continue during storage. Despite its major economic impact, current methods do not provide an efficient solution to manage dry rot. One promising way of managing this disease could be by activating natural defense mechanisms. In this study, we used compounds that suppress tuber sprouting to evaluate their ability to induce natural resistance to dry rot during postharvest storage. Tubers of two cultivars known to be resistant (Asterix) or susceptible (Challenger) to dry rot were treated with sprout suppressors (DMN, MeJa) after harvest. Three days later, tubers were infected with the dry rot pathogen. Tubers were monitored up to three weeks to evaluate the volume of infection, and lab tests were performed to determine the activity of defense-related enzymes. Overall, the results indicated that DMN application significantly reduced the volume of dry rot infection during storage. Additionally, our results suggested that the efficiency of DMN in reducing infection is linked to a direct action on the pathogen rather than the activation of defense mechanism. Taken together, tuber sprout-suppressing compounds may hold promise to manage postharvest storage losses of potato.

Technical Abstract: Fourteen species of Fusarium are associated with dry rot disease in potato tubers. Postharvest losses related to dry rot can reach up to 60% during long-term storage. Current control methods do not provide efficient solution; one promising way of controlling this disease is by activating natural defense mechanisms via elicitors to induce resistance. In this study we evaluated the effects of 1,4-dimethylnaphthalene (DMN) and methyl jasmonate (MeJa) to induce natural resistance to dry rot caused by Fusarium nirenbergiae using a resistant cv. Asterix and susceptible cv. Challenger under cold storage. In vitro and in vivo tests were carried out by evaluating the volume of infection and the activity of antioxidant and defense-related enzymes, including polyphenol oxidase, peroxidase, catalase, ascorbate peroxidase, phenylalanine ammonia-lyase, lipoxygenase and glucanase. The results indicate that the reduction in the volume of infection due to DMN application is not coupled with the expression of evaluated enzymes. Changes observed in such enzyme’s behaviour are likely to be associated with differences in disease susceptibility between cultivars and not with the applied compounds. Our data suggest that the efficiency of DMN in reducing the volume of infection is linked to a direct action on the pathogen rather than the activation of defense mechanism via antioxidant and defense-related enzymes.