Rodríguez-Celma Jorge, Lattanzio Giuseppe, Villarroya Dido, Gutierrez-Carbonell Elain, Ceballos-Laita Laura, Rencoret Jorge, Gutiérrez Ana, Del Río José C, Grusak Michael A, Abadía Anunciación, Abadía Javier, López-Millán Ana-Flor
Plant Nutrition Department, Aula Dei Experimental Station (CSIC), P.O. Box 13034, E-50080, Zaragoza, Spain.
Instituto de Recursos Naturales y Agrobiología de Sevilla (CSIC), Reina Mercedes 10, E-41012 Sevilla, Spain.
J Proteomics. 2016 May 17;140:1-12. doi: 10.1016/j.jprot.2016.03.017. Epub 2016 Mar 30.
Iron deficiency is a yield-limiting factor with major implications for crop production, especially in soils with high CaCO3. Because stems are essential for the delivery of nutrients to the shoots, the aim of this work was to study the effects of Fe deficiency on the stem proteome of Medicago truncatula. Two-dimensional electrophoresis separation of stem protein extracts resolved 276 consistent spots in the whole experiment. Iron deficiency in absence or presence of CaCO3 caused significant changes in relative abundance in 10 and 31 spots, respectively, and 80% of them were identified by mass spectrometry. Overall results indicate that Fe deficiency by itself has a mild effect on the stem proteome, whereas Fe deficiency in the presence of CaCO3 has a stronger impact and causes changes in a larger number of proteins, including increases in stress and protein metabolism related proteins not observed in the absence of CaCO3. Both treatments resulted in increases in cell wall related proteins, which were more intense in the presence of CaCO3. The increases induced by Fe-deficiency in the lignin per protein ratio and changes in the lignin monomer composition, assessed by pyrolysis-gas chromatography-mass spectrometry and microscopy, respectively, further support the existence of cell wall alterations.
In spite of being essential for the delivery of nutrients to the shoots, our knowledge of stem responses to nutrient deficiencies is very limited. The present work applies 2-DE techniques to unravel the response of this understudied tissue to Fe deficiency. Proteomics data, complemented with mineral, lignin and microscopy analyses, indicate that stems respond to Fe deficiency by increasing stress and defense related proteins, probably in response of mineral and osmotic unbalances, and eliciting significant changes in cell wall composition. The changes observed are likely to ultimately affect solute transport and distribution to the leaves.
缺铁是一个限制产量的因素，对作物生产有重大影响，尤其是在碳酸钙含量高的土壤中。由于茎对于向地上部输送养分至关重要，因此本研究的目的是研究缺铁对蒺藜苜蓿茎蛋白质组的影响。茎蛋白提取物的二维电泳分离在整个实验中解析出276个一致的斑点。在有无碳酸钙的情况下缺铁分别导致10个和31个斑点的相对丰度发生显著变化，其中80%通过质谱鉴定。总体结果表明，缺铁本身对茎蛋白质组有轻微影响，而在碳酸钙存在下缺铁有更强的影响并导致更多蛋白质发生变化，包括应激和蛋白质代谢相关蛋白质的增加，而在无碳酸钙时未观察到这种情况。两种处理均导致细胞壁相关蛋白质增加，在有碳酸钙的情况下增加更为明显。通过热解-气相色谱-质谱和显微镜分别评估的缺铁诱导的木质素/蛋白质比率增加和木质素单体组成变化，进一步支持了细胞壁改变的存在。
尽管茎对于向地上部输送养分至关重要，但我们对茎对营养缺乏反应的了解非常有限。本研究应用二维电泳技术来揭示这个研究较少的组织对缺铁的反应。蛋白质组学数据，辅以矿物质、木质素和显微镜分析，表明茎通过增加应激和防御相关蛋白质来应对缺铁，这可能是对矿物质和渗透失衡的反应，并引发细胞壁组成的显著变化。观察到的变化可能最终影响溶质向叶片的运输和分布。
