Title:
|
Understanding the post harvest disorder blackheart in Solanum tuberosum
|
Over a third of the food produced globally for human consumption is wasted each year, representing huge economic losses and limiting the security and efficiency of our food systems. In the UK, almost a half of potato tubers are lost after harvest, with the post-harvest disorder Blackheart accounting for a significant proportion of this wastage. Despite the importance of Blackheart, the underlying cause of the disorder is unclear, preventing its reliable prediction and management in industry. Utilisation of a Blackheart induction method enabled improved characterisation of Blackheart in Solanum tuberosum, identifying it as a tissue specific condition that originates in tuber pith tissues. Although high temperatures and the abundances of CO2 and O2 have long been attributed to causing Blackheart, it was shown that none are necessary for the disorder to develop and instead, multiple conditions influence Blackheart development. Blackheart was associated with a decrease in the ATP:ADP ratio below a threshold level in affected tissues. The production of ATP did not appear to be limited in Blackheart affected tissues, as demonstrated by flux analysis and the abundance of respiratory substrates. Altered redistribution of labelled precursors into lipids and increased lipid acyl hydrolase activity of the potato storage protein, patatin, suggested that that active phospholipid breakdown was responsible for observed increases in membrane leakage. The resulting increased maintenance costs and consumption of ATP are proposed to drive cell death and the polyphenol-oxidase catalysed pigmentation that is observed in Blackheart affected tissues.
|