The metabolic response of cultured tomato cells to low oxygen stress

Abstract

The storage of fruits and vegetables under a controlled atmosphere can induce low oxygen stress, which can lead to post-harvest losses through the induction of disorders such as core breakdown and browning. To gain better understanding of the metabolic response of plant organs to low oxygen, cultured tomato cells (Lycopersicum esculentum) were used as a model system to study the metabolic stress response to low oxygen (0 and 1 kPa O2). By adding 13C labelled glucose, changes in the levels of polar metabolites and their 13C label accumulation were quantified. Low oxygen stress altered the metabolite profile of tomato cells, with the accumulation of the intermediates of glycolysis in addition to increases in lactate and sugar alcohols. 13C label data showed reduced label accumulation in almost all metabolites except lactate and some sugar alcohols. The results showed that low oxygen stress in tomato cell culture activated fermentative metabolism and sugar alcohol synthesis while inhibiting the activity of the TCA cycle and the biosynthesis of metabolites whose precursors are derived from central metabolism, including fluxes to most organic acids, amino acids and sugars.

A Shoot-Specific Hypoxic Response of Arabidopsis Sheds Light on the Role of the Phosphate-Responsive Transcription Factor PHOSPHATE STARVATION RESPONSE1

“…Possibly, the ratio of 3-PGA/Pi could serve as a signal, as it increased under the two stress conditions. Levels of 3-PGA were significantly increased under hypoxia, while they tended to decrease under phosphate deficiency, a trend observed previously (low Pi, Fredeen et al, 1990;Jacob and Lawlor, 1992;Rao and Terry, 1995;and hypoxia, Biemelt et al, 1999;Shingaki-Wells et al, 2011;Ampofo-Asiama et al, 2014).…”

Response of pomegranate arils (cv. Wonderful) to low oxygen stress under active modified atmosphere condition

“…The occurrence of anaerobic respiration was correlated to the microbial growth with the reduction of O 2 concentration. The highest yeast and mould growth at 10 °C could be an indication that there was a slightly acidic environment due to a fermentative condition . Yeast and mould grow relatively better in acidic media than bacteria do .…”

“…Under a low O 2 condition, metabolism can switch from aerobic to anaerobic respiration (fermentation), which enables the continuation of glycolysis and substrate‐level phosphorylation to produce energy in the form of adenosine triphosphate to insure survival. This process can lead to the production of off‐flavour . Therefore, this critical O 2 limit should be avoided when using modified atmosphere packaging (MAP) in order to maintain fruit quality .…”

“…Anaerobic respiration can be detected by the upswing in the respiration quotient (RQ) associated with the synthesis of acetaldehyde, ethanol, and CO 2 . Identification of fermentative volatiles emitted due to anaerobic respiration to understand the response of a horticultural commodity to low O 2 and other abiotic perturbations has gained tremendous attention in the last decade …”

“…This process can lead to the production of off-flavour. 6 Therefore, this critical O 2 limit should be avoided when using modified atmosphere packaging (MAP) in order to maintain fruit quality. 7 According to Beaudry et al 8 the O 2 concentration at which tissue fermentation is induced may be taken as the lowest O 2 limit.…”