Abstract Drought is a major abiotic stress factor that affects the yield of maize (Zea mays L.) during the grain filling period. Therefore, it is critical to reveal the molecular mechanisms underlying maize drought stress tolerance. To analyze the characteristics and functions of differentially abundant proteins (DAPs) in response to drought stress during the maize kernel-filling stage, here, two maize hybrid varieties with contrasting drought tolerance (tolerant ND476 and sensitive ZX978) were subjected to water sufficient (control) and water deficit (drought) treatment conditions for 12 days at the grain filling stage. Physiological assays and leaf proteome analysis were performed. We conducted iTRAQ analysis on 12 samples from 4 groups and obtained 1,655 DAPs. Amongst these, five essential sets of drought responsive DAPs were identified by bioinformatics techniques. Four significantly enriched metabolic pathways were identified in ND476, which were shown to be associated with the ribosome, metabolic, basal transcription factors and photosynthesis pathways. Further, the phenotypic characterization and qRT-PCR analysis confirmed our iTRAQ sequencing data. Remarkably, significantly higher drought tolerance of ND476 may be attributed to the following responses: (a) oxidoreductase, peroxidase and hydrolytic enzyme activities to promote cell redox homeostasis maintenance; (b) elevated expression of stress defense proteins; and (c) reduced synthesis of redundant proteins in order to help plants preserve energy to fight drought stress. In conclusion, these results offer more insights into the molecular mechanisms underlying maize drought tolerance at the grain filling stage and can be a foundational basis for molecular breeding of drought tolerant maize varieties.

中文翻译：

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两个玉米杂交种的比较蛋白质组学分析揭示了干旱胁迫耐受机制

摘要 干旱是影响籽粒灌浆期玉米（Zea mays L.）产量的主要非生物胁迫因素。因此，揭示玉米干旱胁迫耐受性的分子机制至关重要。为了分析玉米灌浆期差异丰度蛋白 (DAP) 响应干旱胁迫的特征和功能，在这里，两个耐旱性不同的玉米杂交品种（耐受性 ND476 和敏感 ZX978）进行了充足的水分（对照） ) 和灌浆期缺水（干旱）处理条件 12 天。进行了生理学测定和叶蛋白质组分析。我们对来自 4 组的 12 个样本进行了 iTRAQ 分析，获得了 1,655 个 DAP。其中，通过生物信息学技术鉴定了五组基本的干旱响应 DAP。在 ND476 中鉴定出四种显着富集的代谢途径，它们被证明与核糖体、代谢、基础转录因子和光合作用途径有关。此外，表型表征和 qRT-PCR 分析证实了我们的 iTRAQ 测序数据。值得注意的是，ND476 显着更高的耐旱性可能归因于以下反应： (a) 氧化还原酶、过氧化物酶和水解酶活性，以促进细胞氧化还原稳态维持；(b) 应激防御蛋白的表达升高；(c) 减少多余蛋白质的合成，以帮助植物保存能量以对抗干旱压力。综上所述，