Browsing by Author "McWilliam, S."

Now showing 1 - 3 of 3
  • Thumbnail Image
    ItemOpen Access
    New insights into the effects of ethylene on ABA catabolism, sweetening and dormancy in stored potato tubers
    (Elsevier, 2020-12-08) Tosetti, R.; Waters, Amanda; Chope, Gemma A.; Cools, K.; Alamar, M. Carmen; McWilliam, S.; Thompson, Andrew J.; Terry, Leon A
    Continuous ethylene supplementation suppresses postharvest sprouting, but it can increase reducing sugars, limiting its use as an alternative to chlorpropham for processing potatoes. To elucidate the mechanisms involved, tubers were treated after curing with or without the ethylene binding inhibitor 1-methylcyclopropene (1-MCP at 1 μL L−1 for 24 h), and then stored in air or air supplemented with continuous ethylene (10 μL L−1). Across three consecutive seasons, changes in tuber physiology were assessed alongside transcriptomic and metabolomic analysis. Exogenous ethylene alone consistently induced a respiratory rise and the accumulation of undesirable reducing sugars. The transient respiratory peak was preceded by the strong upregulation of two genes encoding 1-aminocyclopropane-1-carboxylate oxidase (ACO), typical of wound and stress induced ethylene production. Profiles of parenchymatic tissue highlighted that ethylene triggered abscisic acid (ABA) catabolism, evidenced by a steep fall in ABA levels and a transient rise in the catabolite phaseic acid, accompanied by upregulation of transcripts encoding an ABA 8ˊ-hydroxylase. Moreover, analysis of non-structural carbohydrate-related genes revealed that ethylene strongly downregulated the expression of the Kunitz-type invertase inhibitor, already known to be involved in cold-induced sweetening. All these ethylene-induced effects were negated by 1-MCP with one notable exception: 1-MCP enhanced the sprout suppressing effect of ethylene whilst preventing ethylene-induced sweetening. This study supports the conclusions that: i) tubers adapt to ethylene by regulating conserved pathways (e.g. ABA catabolism); ii) ethylene-induced sweetening acts independently from sprout suppression, and is similar to cold-induced sugar accumulation.
  • No Thumbnail Available
    ItemOpen Access
    New insights into the effects of ethylene on ABA catabolism, sweetening and dormancy in stored potato tubers
    (Cranfield University, 2020-12-09 18:00) del carmen Alamar Gavidia, Maria; Thompson, Andrew; Tosetti, Roberta; A. Chope, Gemma; Cools, Katherine; Waters, Amanda; McWilliam, S.; Terry, Leon
    Underlying data for this paper includes: respiration rate, sprout assessment, sprout incidence, and abscisic acid (ABA) and ABA-metabolites concentration for potato tubers during postharvest storage.
  • Thumbnail Image
    ItemOpen Access
    Optical coherence tomography imaging of potato skin to understand variability in response to pre- and postharvest factors
    (International Society for Horticultural Science (ISHS), 2018-04-30) Landahl, Sandra; Foukaraki, S.; McWilliam, S.; Terry, Leon A
    In order to be able to assess the effect of pre- and postharvest treatments on different potato cultivars and tissues, information is needed on the skin architecture of tubers. Optical coherence tomography (OCT) was utilised as an appropriate non-destructive technique due to its high spatial resolution. It uses near-infra-red optical radiation to map the internal structures of semi-transparent samples. Samples in this study were potatoes with known provenance, under selected pre- or postharvest treatment. The study herein aimed to examine the effect of the growing environment and a desiccant chemical on skin layer development of several potato cultivars and to increase understanding of the variability in skin thickness after application of sprout suppressant. Different thicknesses of the skin layer were found between different farming locations, cultivars and spatial positions on individual tubers (60 to 100 µm). In detail, the spatial difference of skin layer thicknesses developed over time. Duration of the desiccation and curing did not cause significant differences in the skin thickness. However, skin thickness changes were observed during storage and were cultivar dependent. The chlorpropham treatment did not significantly influence the skin layer thickness. Still images recorded by means of OCT were a convenient and non-destructive tool to quantitatively evaluate the skin thickness of potatoes. In conclusion, the high resolution of the acquired still images allowed confirmation of tissue identification. It appears that the tissue position on the tuber may have a higher influence on the phellem thickness than the harvest date or curing.