Different expression of kiwifruit ethylene-related genes during low storage temperatures

Abstract

Autocatalytic ethylene production is the start of a transcription cascade that regulates many important features of fruit quality, including flavoring and softening. Kiwifruit (Actinidia deliciosa) is a climacteric fruit, sensitive to low concentrations of ethylene. In current study, the ethylene biosynthesis at low temperatures (− 0.8, − 0.5 and 0 °C) in A. deliciosa has been investigated. The gene expression of transcription factors (AdERF1 and AdETR1) and the enzymes related to ethylene biosynthesis (AdACO1, AdACO2 and AdACS) have been examined using RT-qPCR. According to the results, for all of the examined genes, the highest expression level was observed at − 0.8 and − 0.5 °C, while the lowest expression level was at 0 °C during storage. However, kiwifruit is usually stored at temperatures below 0 °C. Also, the expression of ACC (1-aminocyclopropane-1-carboxylic acid) oxidase genes (AdACO1 and AdACO2) was higher than that of the other genes, because a low storage temperature is responsible for the activation of the ACC synthase transcript at first and later the ACC oxidase (ACO) transcript. Thus, ACO gene induction appears to be the second signal of chilling stress. The induction of ACO transcripts by chilling preceded the appearance of chilling symptoms. According to the current results, the temperature of 0 °C is the best temperature for storing kiwifruit for a long time.