Salt stress is a major abiotic factor limiting maize yield. To characterize the mechanism underlying maize salt tolerance, we compared the seedling root proteomes of salt-tolerant Jing724 and salt-sensitive D9H. The germination rate and growth parameter values (weight and length) were higher for Jing724 than for D9H under saline conditions. Using an iTRAQ-based method, we identified 513 differentially regulated proteins (DRPs), with 83 and 386 DRPs specific to Jing724 and D9H, respectively. In salt-stressed Jing724, the DRPs were primarily associated with the pentose phosphate pathway, glutathione metabolism, and nitrogen metabolism. Key DRPs, such as glucose-6-phosphate 1-dehydrogenase, NADPH-producing dehydrogenase, glutamate synthase, and glutamine synthetase, were identified based on pathway enrichment and protein–protein interaction analyses. Moreover, salt-responsive proteins in Jing724 seedlings were implicated in energy management, maintenance of redox homeostasis, detoxification of ammonia, regulation of osmotic homeostasis, stress defense and adaptation, biotic cross-tolerance, and regulation of gene expression. Quantitative analyses of superoxide dismutase activity, malondialdehyde content, relative electrolyte leakage, and proline content were consistent with the predicted changes based on DRP functions. Furthermore, changes in the abundance of eight representative DRPs were correlated with the corresponding mRNA levels. Our results may be useful for elucidating the molecular networks mediating salt tolerance.

中文翻译：

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玉米基因型不同的比较蛋白质组学为耐盐胁迫机制提供了见识

盐胁迫是限制玉米产量的主要非生物因素。为了表征玉米耐盐性的潜在机制，我们比较了耐盐的Jing724和盐敏感的D9H的幼苗根蛋白质组。在盐水条件下，Jing724的发芽率和生长参数值（重量和长度）高于D9H。使用基于iTRAQ的方法，我们鉴定了513个差异调节蛋白（DRP），分别具有针对Jing724和D9H的83个和386个DRP。在盐胁迫的Jing724中，DRPs主要与戊糖磷酸途径，谷胱甘肽代谢和氮代谢有关。根据途径富集和蛋白质-蛋白质相互作用分析，确定了关键的DRP，例如6-磷酸葡萄糖1-脱氢酶，产生NADPH的脱氢酶，谷氨酸合酶和谷氨酰胺合成酶。此外，Jing724幼苗中的盐反应蛋白与能量管理，氧化还原稳态的维持，氨的解毒，渗透稳态的调节，逆境防御和适应，生物交叉耐受以及基因表达的调节有关。超氧化物歧化酶活性，丙二醛含量，相对电解质渗漏和脯氨酸含量的定量分析与基于DRP功能的预测变化一致。此外，八个代表性DRP的丰度变化与相应的mRNA水平相关。我们的结果可能有助于阐明介导耐盐性的分子网络。渗透稳态的调节，压力防御和适应，生物交叉耐受以及基因表达的调节。超氧化物歧化酶活性，丙二醛含量，相对电解质渗漏和脯氨酸含量的定量分析与基于DRP功能的预测变化一致。此外，八个代表性DRP的丰度变化与相应的mRNA水平相关。我们的结果可能有助于阐明介导耐盐性的分子网络。渗透稳态的调节，压力防御和适应，生物交叉耐受以及基因表达的调节。超氧化物歧化酶活性，丙二醛含量，相对电解质渗漏和脯氨酸含量的定量分析与基于DRP功能的预测变化一致。此外，八个代表性DRP的丰度变化与相应的mRNA水平相关。我们的结果可能有助于阐明介导耐盐性的分子网络。八个代表性DRP的丰度变化与相应的mRNA水平相关。我们的结果可能有助于阐明介导耐盐性的分子网络。八个代表性DRP的丰度变化与相应的mRNA水平相关。我们的结果可能有助于阐明介导耐盐性的分子网络。