College of Agriculture and Biotechnology/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, China.
Plant Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK.
Plant Cell Environ. 2017 Aug;40(8):1531-1551. doi: 10.1111/pce.12951. Epub 2017 May 11.
Low temperature conditioning (LTC) alleviates peach fruit chilling injury but the underlying molecular basis is poorly understood. Here, changes in transcriptome, ethylene production, flesh softening, internal browning and membrane lipids were compared in fruit maintained in constant 0 °C and LTC (pre-storage at 8 °C for 5 d before storage at 0 °C). Low temperature conditioning resulted in a higher rate of ethylene production and a more rapid flesh softening as a result of higher expression of ethylene biosynthetic genes and a series of cell wall hydrolases. Reduced internal browning of fruit was observed in LTC, with lower transcript levels of polyphenol oxidase and peroxidase, but higher lipoxygenase. Low temperature conditioning fruit also showed enhanced fatty acid content, increased desaturation, higher levels of phospholipids and a preferential biosynthesis of glucosylceramide. Genes encoding cell wall hydrolases and lipid metabolism enzymes were coexpressed with differentially expressed ethylene response factors (ERFs) and contained ERF binding elements in their promoters. In conclusion, LTC is a special case of cold acclimation which increases ethylene production and, operating through ERFs, promotes both softening and changes in lipid composition and desaturation, which may modulate membrane stability, reducing browning and contributing to alleviation of peach fruit chilling injury.
低温驯化（LTC）可减轻桃果实冷害，但其中的分子基础尚不清楚。在这里，比较了在恒定 0°C 和 LTC（在 0°C 下贮藏前在 8°C 下预贮藏 5 天）下贮藏的果实中转录组、乙烯生成、果肉软化、内部褐变和膜脂的变化。低温驯化导致乙烯生成速率更高，果肉软化更快，这是由于乙烯生物合成基因和一系列细胞壁水解酶的表达更高。在 LTC 中观察到果实内部褐变减少，多酚氧化酶和过氧化物酶的转录水平较低，但脂氧合酶较高。低温驯化的果实还表现出脂肪酸含量增加、饱和度增加、磷脂水平升高以及葡糖神经酰胺的优先生物合成。细胞壁水解酶和脂质代谢酶基因与差异表达的乙烯反应因子（ERFs）共表达，并在其启动子中含有 ERF 结合元件。总之，LTC 是一种特殊的冷驯化情况，它增加了乙烯的生成，并通过 ERFs 促进了软化和脂质组成及饱和度的变化，这可能调节了膜的稳定性，减少了褐变，并有助于减轻桃果实的冷害。
