This research was conducted to investigate the mechanism of 1-methylcyclopropene (1-MCP) treatment on ascorbic acid (AsA) content in kiwifruit after harvest. Our findings indicated that 1-MCP treatment postponed the course of fruit senescence and maintained higher contents of AsA and total ascorbic acid (T-AsA) during storage in postharvest kiwifruit. Gene expression analysis revealed that the transcription level of genes involved in AsA metabolic pathway were regulated by 1-MCP treatment. The up-regulation of genes for AsA biosynthesis (AdGME, AdGalDH, AdGalLDH and AdGalUR) and regeneration (AdDHAR and AdGR) and down-regulation of degradation genes (AdAO) collectively contributed to the increase in AsA level in treated kiwifruit during storage. Moreover, the expression level of four candidate bHLH transcription factors, preliminarily screened from the transcriptome database of kiwifruit, was up-regulated by 1-MCP treatment by qPCR analysis. Taken together, our results suggested that due to its positive regulation on numerous ascorbate modifying genes and probably the candidate bHLH transcription factors, 1-MCP had a beneficial effect on AsA content.

本研究旨在研究1-甲基环丙烯（1-MCP）处理对猕猴桃收获后抗坏血酸（AsA）含量的影响机理。我们的研究结果表明，1-MCP处理可延迟水果的衰老过程，并在收获后的猕猴桃贮藏期间保持较高的AsA和总抗坏血酸（T-AsA）含量。基因表达分析表明，通过1-MCP处理可调节AsA代谢途径中相关基因的转录水平。AsA生物合成基因（AdGME，AdGalDH，AdGalLDH和AdGalUR）的上调和再生（AdDHAR和AdGR）和降解基因的下调（AdAO））共同促进了猕猴桃在储存过程中AsA含量的增加。此外，通过qPCR分析通过1-MCP处理上调了从猕猴桃的转录组数据库中初步筛选的四种候选bHLH转录因子的表达水平。两者合计，我们的结果表明，由于1-MCP对许多抗坏血酸修饰基因和候选bHLH转录因子具有积极的调控作用，因此对AsA含量具有有益的影响。