Tepary bean (Phaseolus acutifolius A. Gray) is one of the five species domesticated from the genus Phaseolus with genetic resistance to biotic and abiotic stress. To understand the mechanisms underlying drought responses in seed storage proteins germinated on water and polyethylene glycol (PEG-6000) at -0.49 MPa, we used a proteomics approach to identify potential molecular target proteins associated with the low water potential stress response. Storage proteins from cotyledons of Tepary bean seeds germinated at 24, 48 and 72 h on water and PEG-6000 at -0.49 MPa were analyzed by one-dimensional electrophoresis (DE) with 2-DE analysis and shotgun mass spectrometry. Using computational database searching and bioinformatics analyses, we performed Gene Ontology (GO) and protein interactome (functional protein association network) String analyses. Comparative analysis showed that the effect of PEG-6000 on root growth was parallel to that on germination. Based on the SDS‒PAGE protein banding patterns and 2-DE analysis, ten differentially abundant seed storage proteins showed changes in storage proteins, principally in the phaseolin and lectin fractions. We found many proteins that are recognized as drought stress-responsive proteins, and several of them are predicted to be intrinsically related to abiotic stress. The shotgun analysis searched against UniProt’s legume database, and Gene Ontology (GO) analysis indicated that most of the seed proteins were cytosolic, with catalytic activity and associated with carbohydrate metabolism. The protein‒protein interaction networks from functional enrichment analysis showed that phytohemagglutinin interacts with proteins associated with the degradation of storage proteins in the cotyledons of common bean during germination. These findings suggest that Tepary bean seed proteins provide valuable information with the potential to be used in genetic improvement and are part of the drought stress response, making our approach a potentially useful strategy for discovering novel drought-responsive proteins in other plant models.

中文翻译：

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低水势发芽过程中三叶菜豆种子储存蛋白的蛋白质组学特征

水菜豆 (Phaseolus acutifolius A. Gray) 是从菜豆属驯化的五个物种之一，具有对生物和非生物胁迫的遗传抗性。为了了解在-0.49 MPa的水和聚乙二醇（PEG-6000）上发芽的种子储存蛋白的干旱响应机制，我们使用蛋白质组学方法来识别与低水势胁迫响应相关的潜在分子靶蛋白。通过一维电泳 (DE)、2-DE 分析和鸟枪质谱法对水和 PEG-6000 在 -0.49 MPa 下萌发 24、48 和 72 小时的 Tepary bean 种子子叶的储存蛋白进行分析。使用计算数据库搜索和生物信息学分析，我们进行了基因本体论（GO）和蛋白质相互作用组（功能性蛋白质关联网络）字符串分析。对比分析表明，PEG-6000对根系生长的影响与对发芽的影响是平行的。基于 SDS-PAGE 蛋白质带型和 2-DE 分析，十种不同丰度的种子储存蛋白显示出储存蛋白的变化，主要是在菜豆蛋白和凝集素组分中。我们发现了许多被认为是干旱胁迫响应蛋白的蛋白质，其中一些蛋白质预计与非生物胁迫具有内在相关性。鸟枪法搜索 UniProt 的豆类数据库，基因本体 (GO) 分析表明大多数种子蛋白是胞质蛋白，具有催化活性并与碳水化合物代谢相关。功能富集分析的蛋白质-蛋白质相互作用网络表明，植物血凝素与发芽过程中菜豆子叶中储存蛋白降解相关的蛋白质相互作用。这些发现表明，油菜豆种子蛋白提供了有价值的信息，有可能用于遗传改良，并且是干旱胁迫反应的一部分，使我们的方法成为在其他植物模型中发现新型干旱响应蛋白的潜在有用策略。