In non-climacteric fruits, the respiratory increase is absent and no phytohormone is appearing to be critical for their ripening process. They must remain on the parent plant to enable full ripening and be picked at or near the fully ripe stage to obtain the best eating quality. However, huge losses often occur for their quick post-harvest senescence. To understanding the complex mechanism of non-climacteric fruits post-harvest senescence, we constructed two small RNA libraries and one degradome from strawberry fruit stored at 20°C for 0 and 24 h. A total of 88 known and 1224 new candidatemiRNAs, and 103 targets cleaved by 19 known miRNAs families and 55 new candidatemiRNAs were obtained. These targets were associated with development, metabolism, defense response, signaling transduction and transcriptional regulation. Among them, 14 targets, including NAC transcription factor, Auxin response factors (ARF) and Myb transcription factors, cleaved by 6 known miRNA families and 6 predicted candidates, were found to be involved in regulating fruit senescence. The present study provided valuable information for understanding the quick senescence of strawberry fruit, and offered a foundation for studying the miRNA-mediated senescence of non-climacteric fruits.
The post-harvest ripening of pineapples can be effectively postponed by refrigerated storage. Nevertheless, internal browning (IB) frequently appears in pineapples after refrigerated storage during the course of the shelf life at room temperature, which is known as chilling injury (CI). In this study, the chilling injury of pineapple fruit was induced by a low temperature (6 °C) and transferred to normal-temperature storage; the best concentration of 50 μmol/L of CaCl2 was selected by the IB appearance and electrical conductivity. Fruit quality, reactive oxygen species (ROS), antioxidants, and transcription factors were investigated. The physiological data results indicated that pineapples treated with 50 μmol/L of CaCl2 maintained fruit quality, decreased reactive oxygen species (ROS), and enhanced the antioxidant activity of fruits, alleviating internal browning (IB) symptoms in pineapple fruit. The expressions of related genes were also consistent with the physiological changes by the transcriptome data analysis. In addition, we focused on some related metabolic pathways, including phenylpropanoid biosynthesis, MAPK pathway, plant hormone, plant–pathogen interaction, tricarboxylic acid cycle (TAC), and fatty acid biosynthesis. We performed integrative analyses of transcriptome data combined with a series of physiology and experimental analyses on the internal browning of pineapples, which will be of great significance to extending the shelf life of pineapples through molecular biology in the future.
The aroma, taste, and flavour profiles of mango cultivars vary, directly influencing their marketability and consumer acceptance. In this study, we explored the effects of volatile organic compounds (VOCs) on the distinct aromas of two mango cultivars during storage using GC-IMS and HS-SPME-GC-MS combined with OPLS-DA analysis. Our findings revealed that the terpene and aldehyde contents were higher in the ‘Tainong’ mango cultivar, compared to the ‘Hongyu’ mango, while the ester content was lower. The aroma was attributed to the presence of terpinolene, 2-nonenal, delta-carene, and alpha-phellandrene in the early stages of storage, and later—between 5 and 11 days—to ethyl acetate, ethyl butyrate, and ethyl propanoate. Further analysis of characteristic VOCs using OPLS-DA demonstrated and explained the strong grassy aroma of the ‘Tainong’ mango, and the strong fruity and sweet aromas of the ‘Hongyu’ mango. Additionally, esters mainly accumulated during the later periods of storage, especially propyl butyrate, which was produced and accumulated when fruit quality deteriorated in the later storage period. Our study provides a theoretical basis for detecting mango VOCs during storage to determine the appropriate marketing time for the two mango cultivars and enables informed consumer choice.