Biochimie et Physiologie Moleculaire des Plantes, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, Université Montpellier 2, SupAgro. Bat 7, 2 place Viala, 34060 Montpellier cedex 1, France.
Ann Bot. 2010 May;105(5):811-22. doi: 10.1093/aob/mcp128. Epub 2009 May 29.
Iron is an essential element for both plant productivity and nutritional quality. Improving plant iron content was attempted through genetic engineering of plants overexpressing ferritins. However, both the roles of these proteins in plant physiology, and the mechanisms involved in the regulation of their expression are largely unknown. Although the structure of ferritins is highly conserved between plants and animals, their cellular localization differs. Furthermore, regulation of ferritin gene expression in response to iron excess occurs at the transcriptional level in plants, in contrast to animals which regulate ferritin expression at the translational level.
In this review, an overview of our knowledge of bacterial and mammalian ferritin synthesis and functions is presented. Then the following will be reviewed: (a) the specific features of plant ferritins; (b) the regulation of their synthesis during development and in response to various environmental cues; and (c) their function in plant physiology, with special emphasis on the role that both bacterial and plant ferritins play during plant-bacteria interactions. Arabidopsis ferritins are encoded by a small nuclear gene family of four members which are differentially expressed. Recent results obtained by using this model plant enabled progress to be made in our understanding of the regulation of the synthesis and the in planta function of these various ferritins.
Studies on plant ferritin functions and regulation of their synthesis revealed strong links between these proteins and protection against oxidative stress. In contrast, their putative iron-storage function to furnish iron during various development processes is unlikely to be essential. Ferritins, by buffering iron, exert a fine tuning of the quantity of metal required for metabolic purposes, and help plants to cope with adverse situations, the deleterious effects of which would be amplified if no system had evolved to take care of free reactive iron.
铁是植物生产力和营养质量的必需元素。通过过表达铁蛋白的植物遗传工程来提高植物铁含量。然而，这些蛋白质在植物生理学中的作用及其表达调控的机制在很大程度上尚不清楚。尽管植物和动物之间的铁蛋白结构高度保守，但它们的细胞定位不同。此外，植物中铁蛋白基因表达的调控是在转录水平上发生的，而动物则是在翻译水平上调控铁蛋白的表达。
本文综述了我们对细菌和哺乳动物铁蛋白合成和功能的认识。然后将回顾以下内容：（a）植物铁蛋白的特定特征；（b）它们在发育过程中的合成调控以及对各种环境信号的反应；（c）它们在植物生理学中的功能，特别强调细菌和植物铁蛋白在植物-细菌相互作用中的作用。拟南芥铁蛋白由四个成员的小核基因家族编码，这些成员的表达存在差异。利用这种模式植物获得的最新结果使我们对这些各种铁蛋白的合成调控及其在植物体内功能的理解取得了进展。
对植物铁蛋白功能和合成调控的研究表明，这些蛋白质与抗氧化应激的保护之间存在很强的联系。相比之下，它们在各种发育过程中提供铁的潜在铁储存功能不太可能是必需的。铁蛋白通过缓冲铁，对代谢所需金属的数量进行微调，并帮助植物应对不利情况，如果没有进化出一种系统来处理游离的反应性铁，这些不利情况的影响将加剧。
