Protein N-glycosylation plays key roles in protein folding, stability, solubility, biogenesis, and enzyme activity. Tomato (Solanum lycopersicum L.) is an important vegetable crop with abundant nutritional value, and the formation of tomato fruit qualities primarily occurs in the fruit ripening process. However, a large number of N-glycosylation-mediated mechanisms in regulating tomato fruit ripening have not been elucidated to date. In this study, western blot assays showed that the extents of mature N-glycoproteins were differentially expressed in mature green fruits (fruit start ripening) and ripe fruits (fruit stop ripening). Next, through performing a comparative N-glycoproteome analysis strategy, a total of 553 N-glycosites from 363 N-glycoproteins were identified in mature green fruits compared with ripe fruits. Among them, 252 N-glycosites from 191 N-glycoproteins were differentially expressed in mature green fruits compared with ripe fruits. The differentially expressed N-glycoproteins were mainly located in the chloroplast (30 %) and cytoplasm (16 %). Gene Ontology (GO) analysis showed that these N-glycoproteins were involved in various biological processes, cellular components and molecular functions. These N-glycoproteins participate in biological processes, such as metabolic processes, cellular processes and single-organism processes. These N-glycoproteins are also cellular components in biological process cells, membranes and organelles and have different molecular functions, such as catalytic activity and binding. Notably, these N-glycoproteins were enriched in starch and sucrose metabolism and galactose metabolism by KEGG pathway analysis. This community resource regarding N-glycoproteins is the first large-scale N-glycoproteome during plant fruit ripening. This study will contribute to understanding the function of N-glycosylation in regulating plant fruit ripening.

中文翻译：

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比较 N-糖蛋白质组分析为番茄 (Solanum lycopersicum L.) 在果实成熟过程中的调控机制提供了新的见解

蛋白质 N-糖基化在蛋白质折叠、稳定性、溶解性、生物发生和酶活性方面起着关键作用。番茄（Solanum lycopersicum L.）是一种重要的蔬菜作物，具有丰富的营养价值，番茄果实品质的形成主要发生在果实成熟过程中。然而，迄今为止，大量 N-糖基化介导的番茄果实成熟调控机制尚未阐明。在这项研究中，蛋白质印迹分析表明成熟 N-糖蛋白的程度在成熟的绿色果实（果实开始成熟）和成熟果实（果实停止成熟）中差异表达。接下来，通过执行比较 N-糖蛋白质组分析策略，与成熟水果相比，在成熟的绿色水果中从 363 个 N-糖蛋白中总共鉴定了 553 个 N-糖位点。他们之中，与成熟果实相比，成熟绿色果实中 191 个 N-糖蛋白中的 252 个 N-糖位点差异表达。差异表达的N-糖蛋白主要位于叶绿体（30%）和细胞质（16%）中。基因本体论（GO）分析表明，这些N-糖蛋白参与了各种生物过程、细胞成分和分子功能。这些N-糖蛋白参与生物过程，例如代谢过程、细胞过程和单一生物过程。这些 N-糖蛋白也是生物过程细胞、膜和细胞器中的细胞成分，具有不同的分子功能，例如催化活性和结合。值得注意的是，通过 KEGG 通路分析，这些 N-糖蛋白富含淀粉和蔗糖代谢以及半乳糖代谢。这种关于 N-糖蛋白的社区资源是植物果实成熟过程中的第一个大规模 N-糖蛋白组。本研究将有助于了解 N-糖基化在调节植物果实成熟中的作用。