The great strawrobbery – What is cold storage stealing from the strawberry?

A.P. Baldwin, H.J. Rogers, H. W. Nützmann, N. Kent

Cardiff School of Biosciences, Cardiff university, Sir Martin Evans Building, The, Museum Ave, Cardiff CF10 3AX

Fruit intake is an important component of a healthy diet, but also results in a high level of post-harvest waste. Strawberries (Fragaria x ananassa) have a short shelf life and are therefore transported and stored at low temperatures. However, cold storage can be considered as a ‘necessary evil’ since it is required to prolong postharvest shelf life but also down-regulates metabolism. This results in loss of flavour for the consumer. Characteristic strawberry aroma and flavour is due to the production of a complex mixture of volatile organic compounds (VOCs).  Gas chromatography mass spectrometry (GC-MS) analysis, shows that VOC profiles differ over growing seasons and during cold storage. Esters are the most abundant VOC and are synthesised by alcohol acyltransferase (AAT) whose expression decreases over cold storage. Transient over-expression of AAT during cold storage, alters ester profiles highlighting the importance of AAT for aroma. A transcriptomic analysis of strawberry fruit during cold storage shows that >1000 genes change in expression including several transcription factors which are co-expressed with AAT. ChIP-seq data indicates that the H3K27me3 mark (histone silencing mark) may be an important regulator of gene expression. Understanding these layers of control can provide useful markers for targeted breeding to improve shelf life and quality for the consumer thus reducing waste.