Articles
Preharvest stress in rocket salad leaves results in postharvest metabolic and gene expression changes during chilled storage
Article number
1442_7
Pages
49 – 56
Language
English
Abstract
Rocket salad (Diplotaxis tenuifolia L.) is appreciated for its peppery flavour and nutritional content.
It is grown across temperate regions both under cover and in the open field, exposing it to numerous stresses including cold, heat and flooding.
Its postharvest shelf-life is prolonged by refrigeration, but this imposes stress on the young leaves.
We tested whether preharvest stress affects rocket salad leaves postharvest when exposed to chilled storage.
We exposed rocket salad plants to cold, heat or flood stress just before harvest after 30 d growth followed by storage until 21 d at 6°C. VOC profiles were recorded at harvest and after storage in control and stressed leaves using thermal desorption gas chromatography time of flight mass spectroscopy (TD-GC-TOF-MS). VOC profiles were significantly affected by the preharvest stresses even after 1 week of chilled storage compared to controls.
Expression of two stress-responsive NAC transcription factors (DtNAC59 and DtNAC19) was assessed using reverse transcription qPCR. Expression of both genes increased in response to the cold storage both under control growth conditions and with preharvest stress.
The increase in expression following preharvest heat and flood stress was accentuated for DtNAC59 but only following flood stress for DtNAC19. To further explore the effects of heat stress, we assessed physiological and transcriptomic changes.
Chlorophyll, photosynthetic efficiency and ion leakage showed little change but over 900 genes changed in expression following preharvest heat treatment and 7 d of chilled storage.
Gene Ontology GO term analysis of over-represented terms after 1 week of chilled storage showed that one of the most affected functions was stress responses.
It is grown across temperate regions both under cover and in the open field, exposing it to numerous stresses including cold, heat and flooding.
Its postharvest shelf-life is prolonged by refrigeration, but this imposes stress on the young leaves.
We tested whether preharvest stress affects rocket salad leaves postharvest when exposed to chilled storage.
We exposed rocket salad plants to cold, heat or flood stress just before harvest after 30 d growth followed by storage until 21 d at 6°C. VOC profiles were recorded at harvest and after storage in control and stressed leaves using thermal desorption gas chromatography time of flight mass spectroscopy (TD-GC-TOF-MS). VOC profiles were significantly affected by the preharvest stresses even after 1 week of chilled storage compared to controls.
Expression of two stress-responsive NAC transcription factors (DtNAC59 and DtNAC19) was assessed using reverse transcription qPCR. Expression of both genes increased in response to the cold storage both under control growth conditions and with preharvest stress.
The increase in expression following preharvest heat and flood stress was accentuated for DtNAC59 but only following flood stress for DtNAC19. To further explore the effects of heat stress, we assessed physiological and transcriptomic changes.
Chlorophyll, photosynthetic efficiency and ion leakage showed little change but over 900 genes changed in expression following preharvest heat treatment and 7 d of chilled storage.
Gene Ontology GO term analysis of over-represented terms after 1 week of chilled storage showed that one of the most affected functions was stress responses.
Authors
L. Alotaibi, S.R. Christofides, C. Wilson, C.T. Müller, N.D. Spadafora, H.J. Rogers
Keywords
Diplotaxis tenuifolia, gene expression, plant stress, rocket salad, transcriptome
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