Li Rui, Ma Jiheng, Gu Hui, Jia Wenjun, Shao Yuanzhi, Li Wen
Key Laboratory for Quality Regulation of Tropical Horticultural Crops of Hainan Province, School of Horticulture, Hainan University, Haikou, China.
Key Laboratory of Hainan Province for Postharvest Physiology and Technology of Tropical Horticultural Products, South Subtropical Crops Research Institute, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang, China.
Front Plant Sci. 2022 Sep 20;13:971050. doi: 10.3389/fpls.2022.971050. eCollection 2022.
Ethylene burst is an important sign of the initiation of postharvest mango ripening and softening is a typical characteristic of fruit ripening. However, the intrinsic link between ethylene release and fruit softening during ripening of postharvest mangoes is still not clear. The aim of this study was to investigate the effects of ethylene and its action inhibitor 1-methylcyclopropene (1-MCP) on fruit softening and ripening and the underlying regulatory mechanisms. Results showed that ethephon (ETH) promoted ethylene release and enhanced MDA content and activities of cell wall degrading enzymes, whereas 1-MCP treatment exhibited an opposite effect. Moreover, real-time quantitative polymerase chain reaction indicated that the transcription levels of genes involved in cell wall degradation (, and ), ethylene biosynthesis ( and ) and ethylene response factor () were remarkably induced by ETH. Correlation analysis further revealed that the production of ethylene was significantly negatively correlated with firmness, but positively correlated with MDA content, activities of cell wall degrading enzymes and expressions of and . Furthermore, yeast one hybrid (Y1H) assay showed that MiERF2 and MiERF8 could directly bind to the promotor of and then regulate its transcription. These findings suggest that ethylene production is closely associated with fruit softening, and MiERF2 and MiERF8 and may play crucial roles in regulation of ripening and softening of postharvest mangoes.
乙烯爆发是采后芒果成熟启动的重要标志，而软化是果实成熟的典型特征。然而，采后芒果成熟过程中乙烯释放与果实软化之间的内在联系仍不明确。本研究的目的是探讨乙烯及其作用抑制剂1-甲基环丙烯（1-MCP）对果实软化和成熟的影响及其潜在调控机制。结果表明，乙烯利（ETH）促进乙烯释放，提高丙二醛含量和细胞壁降解酶活性，而1-MCP处理则表现出相反的效果。此外，实时定量聚合酶链反应表明，ETH显著诱导了参与细胞壁降解（、和）、乙烯生物合成（和）以及乙烯反应因子（）的基因的转录水平。相关性分析进一步表明，乙烯的产生与硬度显著负相关，但与丙二醛含量、细胞壁降解酶活性以及和的表达正相关。此外，酵母单杂交（Y1H）试验表明，MiERF2和MiERF8可以直接结合到的启动子上，进而调控其转录。这些结果表明，乙烯的产生与果实软化密切相关，MiERF2、MiERF8和可能在采后芒果成熟和软化的调控中起关键作用。
