Wild rocket (Diplotaxis tenuifolia L.) has a great value in the fresh-cut industry thanks to its nutritional and sensory properties. Nonetheless, the molecular mechanisms that confer harvested leaves their tolerances to pre- and post-harvest stress during processing and throughout their shelf-life have never been studied.
Researchers from the University of Milan and Cardiff, the same ones involved in the EU Quafety project between 2012 and 2015, conducted a first transcriptomic analysis of rocket through the assembly of de novo RNA sequences, functional annotation and stress-induced expression analysis of 33,874 transcripts.
Rocket was subjected to various stresses. Pre-harvest stresses were increased salinity, heat and nitrogen starvation, while post-harvest stresses were cold, dehydration, dark and wounding.
Transcriptomic changes were analysed 24 hours after the stress was applied. Tanscription factors and the genes involved in plant growth regulation, autophagy, senescence and glucosinolate metabolism were the most affected mechanisms.
"We identified hundreds of genes with an unknown function but which only expressed in stressful conditions. They supplied us with important information to study stress response. Dehydration and wounding had the strongest effects on the transcriptome and the various stresses induced changes in the expression of genes correlated to overlapping groups of hormones. These data will enable the development of approaches to improve stress tolerance, quality and shelf-life with direct applications in the fresh-cut industry."
Source: Cavaiuolo M., Cocetta G., Spadafora N.D., Müller C.T., Rogers H.J., Ferrante A., 'Gene expression analysis of rocket salad under pre-harvest and postharvest stresses: A transcriptomic resource for Diplotaxis tenuifolia', 2017, PLOS ONE, Vol. 12(5): e0178119.