The role of proline in superficial scald development in pear fruit was investigated in this study. During low temperature storage of ‘Dangshansuli’ pear fruit, superficial scald incidence and index accumulated in association with the alternation of α-farnesene and conjugated trienols (CTols). 14 out of 17 free amino acids were identified; proline content gradually decreased, which was consistent with the up-regulation of PbrP5CS activity and down-regulation of PbrProDH activity in its metabolic pathway. A total of 14 genes involved in proline metabolism were identified based on transcriptome annotation with diverse expression profiles. Results from correlation analysis among proline content further indicate that enzyme activity and gene expression profile, PbrProDH2, PbrProDH4, PbrProDH5 & PbrP5CS5 might play a critical role in proline metabolism during low temperature storage of ‘Dangshansuli’ fruit; thus, influencing superficial scald development which was then functionally validated using the transgenic pear fruit. Postharvest 1-MCP and diphenylamine (DPA) treatment inhibited the accumulation of CTols, and thus, mitigated superficial scald development and maintained higher proline content, in association with the up-regulated PbrP5CS activity, PbrP5CS4 & PbrP5CS5 mRNAs as well as the down-regulated PbrProDH activity & PbrProDH4 transcripts. In a further study, we found that exogenous application of proline alleviated superficial scald incidence and index. To that end, the results of our study confirmed that proline was involved in superficial scald development during pear storage.

本研究调查了脯氨酸在梨果实表面烫伤发展中的作用。'砀山苏里'梨果实在低温贮藏过程中，随着α-法呢烯和共轭三烯醇（CTols）的交替，表面烫伤发生率和指数积累。鉴定了 17 个游离氨基酸中的 14 个；脯氨酸含量逐渐降低，这与其代谢途径中PbrP5CS活性的上调和PbrProDH活性的下调一致。基于具有不同表达谱的转录组注释，共鉴定了 14 个参与脯氨酸代谢的基因。脯氨酸含量相关性分析结果进一步表明酶活性与基因表达谱、PbrProDH2、PbrProDH4、PbrProDH5和PbrP5CS5在'砀山苏里'果实低温贮藏过程中可能在脯氨酸代谢中起关键作用；因此，影响表面烫伤的发展，然后使用转基因梨果实进行功能验证。收获后 1-MCP 和二苯胺 (DPA) 处理抑制了 CTols 的积累，从而减轻了表面烫伤的发展并保持了较高的脯氨酸含量，这与 PbrP5CS 活性、PbrP5CS4和PbrP5CS5 mRNA 的上调以及下调有关PbrProDH 活性和PbrProDH4成绩单。在进一步的研究中，我们发现外源性应用脯氨酸可减轻浅表烫伤的发生率和指数。为此，我们的研究结果证实脯氨酸参与了梨储存过程中表面烫伤的发展。