What do microRNA concentrations tell us about the mechanical damage and storage period of strawberry fruits?

Although much research has been performed to investigate the effects of storage conditions, such as mechanical damage and storage period, on the morphological and physiological properties of strawberry fruits, almost all of them have considered severe stress conditions. Finding fruit characteristics that exert significant changes even toward mild and moderate stress conditions can help provide valuable information about the fruit quality during storage. This study aims to investigate various characteristics of strawberry fruits during storage to determine which type of fruit characteristics exert such significant changes toward stress conditions. Identical strawberry samples were subjected to mechanical loading at three levels (1, 2, and 3 N) and then stored at 6 °C for 13 days. Morphological and physiological features, as well as the concentration of several microRNAs involved in strawberry storage, were measured at three-day intervals. The effects of mechanical loading on morphological and physiological characteristics were not significant, while their effects were significant on miR-164, miR-167, and miR-399a. Moreover, while low correlation coefficients were observed between the fruit morphophysiological traits (< 0.6) toward storage conditions, high correlations were obtained between the concentrations of microRNAs. Instead of measuring the morphological and physiological characteristics of fruits, whose behavior is not generally specific toward the stresses, the results show that microRNA concentrations, which can be measured by an electrochemical biosensor, provide us with noteworthy information about fruit quality during storage. These small non-coding molecules exhibited remarkable responses even in mild and moderate stress conditions, making them reliable markers of fruit quality assessment.