Abstract The effects of exogenous GA4+7 and BA + CPPU treatments at flowering on fruit traits, lignin, and metabolome were investigated in fruit of Japanese pear “Gold Nijisseiki”. Analysis of fruits in all treatments showed that both total and noncondensed lignin content increased early in fruit development and decreased toward harvest and that the core had higher lignin content than the flesh. The core of BA + CPPU-treated fruit had higher maximum total lignin content than did GA4+7-treated and control fruit at early fruit development. At harvest, the total lignin and noncondensed lignin content of BA + CPPU-treated fruit was higher than that of GA4+7-treated and control fruit. The lignin was composed of guaiacyl-syringyl types and the syringyl/guaiacyl (S/G) ratio increased during early stages and remained relatively stable toward harvest. These results suggest that exogenous GA4+7 and BA + CPPU treatment affected only the lignin content, not the S/G ratio. In total, 122 substances were used for metabolome analysis. Partial least squares discriminant analysis first divided substances into clusters corresponding to core and flesh and then separated the clusters of substances associated with GA4+7 treatment from those associated with the BA + CPPU treatment and control. Of these 122 metabolites, 40 were subjected to hierarchical cluster analysis. Among these, 8 metabolites were more abundant in the pear fruit core. The remaining 32 metabolites were more abundant in flesh and differed in abundance among treatments. The functional metabolite arbutin was more abundant in core than in flesh. In contrast, beta-nicotinamide ribotide was more abundant in flesh than in core.

中文翻译：

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外源GA4 + 7 和BA + CPPU 处理对日本梨“金Nijisseiki”果实木质素及初级代谢产物的影响

摘要 研究了外源GA4+7和BA+CPPU处理在开花期对日本梨“金Nijisseiki”果实性状、木质素和代谢组的影响。对所有处理中果实的分析表明，总木质素和非浓缩木质素含量在果实发育早期均有所增加，而在收获时则有所下降，并且果核的木质素含量高于果肉。在果实发育早期，BA + CPPU 处理的果实的核心具有比 GA4+7 处理和对照果实更高的最大总木质素含量。收获时，BA + CPPU 处理的果实的总木质素和非浓缩木质素含量高于 GA4+7 处理和对照果实的总木质素含量。木质素由愈创木酰基-丁香酰基类型组成，并且丁香酰基/愈创木酰基 (S/G) 比率在早期阶段增加，并在收获前保持相对稳定。这些结果表明外源 GA4+7 和 BA + CPPU 处理仅影响木质素含量，而不影响 S/G 比。总共有 122 种物质用于代谢组学分析。偏最小二乘判别分析首先将物质分成对应于核和肉的簇，然后将与 GA4+7 处理相关的物质簇与与 BA + CPPU 处理和对照相关的物质簇分开。在这 122 种代谢物中，有 40 种进行了层次聚类分析。其中，梨果核中含量较多的有8种代谢物。其余 32 种代谢物在果肉中含量更高，并且在不同处理间的丰度不同。功能代谢物熊果苷在核心中比在肉中更丰富。相比之下，β-烟酰胺核糖苷在肉中比在核心中更丰富。