Pia Heltoft Thomsen
Research Scientist
Biography
I am a scientist and expert on potatoes and vegetables. My research is mainly concentrated on storage and postharvest where I focus on product quality, physiology and pathology.
Education:
2010-2016: PhD. Norwegian University of Life Science
2008-2010: Cand. Agro, University of Copenhagen
2004-2007: Bachelor i naturressourcer, University of Copenhagen
Abstract
Carrot (Daucus carota L. subsp. sativus) is a major vegetable crop in Norway which is stored up to 9 months in refrigerated storage rooms. Postharvest storage losses—primarily from water loss, respiration, and fungal decay—can reach up to 30 %. This study investigated the effects of different postharvest pre-storage strategies involving wound healing (WH) and temperature adaptation (TA) on mass loss, respiration rate, polyacetylene content, and disease development in four carrot cultivars (Nelson, Triton, Nominator, and Romance) during long- term storage. Carrots were subjected to six pre-storage strategies combining WH at 10 ◦ and various TA regimes (directly to 0 ◦ C or 1 ◦ C (60 % or 95–98 % RH) C reduction/day), followed by storage at 0 ◦ C for six months. Data showed that WH at high humidity, followed by gradual cooling, reduced disease incidence and increased the accumulation of antifungal polyacetylenes such as falcarinol and falcarindiol-3-acetate. Respiration rates were initially higher under WH treatments but did not result in increased total storage losses. Rapid cooling without WH led to higher disease levels, particularly in the cultivars Nelson and Romance. The findings support the implementation of a wound healing period prior to temperature reduction as a strategy to reduce postharvest decay and improve carrot storage quality, especially under commercial storage conditions where cooling rates may vary.
Abstract
Potato Fusarium dry rot and wilt are the most important soil- and seed-borne diseases in potatoes. They cause high economic losses during potato growth and storage across the world. Previous observations have shown that dryocrassin ABBA can induce resistance in potatoes. However, little is known about whether dryocrassin ABBA can suppress Fusarium oxysporum. In this research, we determined that exogenous dryocrassin ABBA significantly inhibited the mycelial growth, changed the cell ultrastructure, increased the MDA content, and decreased the antioxidant enzyme activity of F. oxysporum. The transcriptome analysis of F. oxysporum with or without dryocrassin ABBA indicated that 1244 differentially expressed genes (DEGs) were identified, of which 594 were upregulated and 650 were downregulated. GO term analysis showed that the DEGs were mostly related to biological processes. The KEGG pathway was mainly related to carbohydrate, amino acid, and lipid metabolism. Moreover, most of the expressions of PCWDEs, HSPs, and MFS were downregulated, decreasing the stress capacity and weakening the pathogenicity of F. oxysporum with dryocrassin ABBA treatment. These findings contribute to a new understanding of the direct functions of dryocrassin ABBA on F. oxysporum and provide a potential ecofriendly biocontrol approach for potato Fusarium dry rot and wilt
Authors
Pia Heltoft ThomsenAbstract
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