The critical node (CN, 85% germination) of seed viability is an important threshold for seed regeneration decisions after long-term conservation. Dependent on the germplasm, the storage period until CN is reached varies and information on the divergence of the proteomic profiles is limited. Therefore, the study aims to identify key proteins and mechanisms relevant for a long plateau phase and a late CN during artificial seed aging of wheat. Seeds of the storage-tolerant genotype (ST) TRI 23248, and the storage-sensitive genotype (SS) TRI 10230 were exposed to artificial ageing (AA) and extracted embryos of imbibed seeds were analyzed using an iTRAQ-based proteomic technique. ST and SS required AA for 24 and 18 days to reach the CN, respectively. Fifty-seven and 165 differentially abundant proteins (DAPs) were observed in the control and aged groups, respectively. Interestingly, a higher activity in metabolic processes, protein synthesis, transcription, cell growth/division, and signal transduction were already found in imbibed embryos of control ST seeds. After AA, 132 and 64 DAPs were accumulated in imbibed embryos of both aged ST and SS seeds, respectively, which were mainly associated with cell defense, rescue, and metabolism. Moreover, 78 DAPs of ST appeared before CN and were mainly enriched in biological pathways related to the maintenance of redox and carbon homeostasis and they presented a stronger protein translation ability. In contrast, in SS, only 3 DAPs appeared before CN and were enriched only in the structural constituents of the cytoskeleton. In conclusion, a longer span of plateau phase might be obtained in seeds when proteins indicate an intense stress response before CN and include the effective maintenance of cellular homeostasis, and avoidance of excess accumulation of cytotoxic compounds. Although key proteins, inherent factors and the precise regulatory mechanisms need to be further investigated, the found proteins may also have functional potential roles during long-term seed conservation.

中文翻译：

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不同耐贮性小麦种子活力丧失关键节点的比较蛋白质组学。

种子活力的关键节点（CN，85% 发芽）是长期保存后种子再生决策的重要阈值。根据种质的不同，达到 CN 的储存期各不相同，并且关于蛋白质组图谱差异的信息有限。因此，本研究旨在确定小麦人工种子老化过程中与长平台期和晚 CN 相关的关键蛋白质和机制。将耐贮基因型 (ST) TRI 23248 和贮藏敏感基因型 (SS) TRI 10230 的种子进行人工老化 (AA)，并使用基于 iTRAQ 的蛋白质组学技术分析吸收种子的提取胚胎。ST 和 SS 分别需要 24 天和 18 天的 AA 才能到达 CN。在对照组和老年组中分别观察到 57 和 165 种差异丰富的蛋白质 (DAP)。有趣的是，已经在对照 ST 种子的吸收胚胎中发现了在代谢过程、蛋白质合成、转录、细胞生长/分裂和信号转导方面的更高活性。AA后，老化ST和SS种子的吸水胚中分别积累了132和64个DAP，主要与细胞防御、拯救和代谢有关。此外，78个ST的DAP出现在CN之前，主要富集在与维持氧化还原和碳稳态相关的生物途径中，它们表现出更强的蛋白质翻译能力。相比之下，在 SS 中，只有 3 个 DAP 出现在 CN 之前，并且仅在细胞骨架的结构成分中富集。综上所述，当蛋白质在 CN 之前表现出强烈的应激反应并包括有效维持细胞稳态和避免细胞毒性化合物的过度积累时，可能会在种子中获得更长的平台期。尽管需要进一步研究关键蛋白质、内在因素和精确的调控机制，但发现的蛋白质在长期种子保存过程中也可能具有潜在的功能作用。