Subcellular dynamics studies of iron reveal how tissue-specific distribution patterns are established in developing wheat grains.
Subcellular dynamics studies of iron reveal how tissue-specific distribution patterns are established in developing wheat grains.
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DOI：
10.1111/nph.17440
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发表时间：
2021-04
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通讯作者：
Sadia Sheraz;Y. Wan;Eudri Venter;S. Verma;Qing Xiong;Joshua Waites;James M. Connorton;P. Shewry;K. Moore;J. Balk
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文献类型：
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作者：
Sadia Sheraz;Y. Wan;Eudri Venter;S. Verma;Qing Xiong;Joshua Waites;James M. Connorton;P. Shewry;K. Moore;J. Balk
了解植物中铁的运输机制是提高作物营养质量的关键。因为很难对铁在运输中进行成像，所以我们目前对铁在发育种子中的转运途径以及如何建立组织特异性分布的了解不完整。我们已经使用了一种新的方法，结合57 Fe同位素标记和纳米二次离子质谱（NanoSIMS），可视化未成熟小麦籽粒，小麦L.组织和细胞内的铁转运。这使我们能够通过不同的细胞类型跟踪铁从母体组织运输到胚胎的主要途径。通过遗传将铁转移到储存空泡中提供了该途径的进一步证据，并通过组织学染色和TEM-EDS提供了确认。几乎所有的铁在控制和转基因谷物被发现在细胞内机构，共质体，而不是质外体运输。此外，一种新型的铁体，高度富集在57铁，观察糊粉细胞，并可能代表铁被交付到植酸球状体。通过NanoSIMS获得的57 Fe富集曲线与组织特异性基因表达的相关性提供了谷物中铁稳态的更新模型，与未来的生物强化策略相关。
Understanding the mechanisms of iron trafficking in plants is key to enhancing the nutritional quality of crops. Because it is difficult to image iron in transit, we currently have an incomplete picture of the route(s) of iron translocation in developing seeds and how the tissue-specific distribution is established. We have used a novel approach, combining 57 Fe isotope labelling and Nanoscale Secondary Ion Mass Spectrometry (NanoSIMS), to visualize iron translocation between tissues and within cells in immature wheat grain, Triticum aestivum L. This enabled us to track the main route of iron transport from maternal tissues to the embryo through the different cell types. Further evidence for this route was provided by genetically diverting iron into storage vacuoles, with confirmation provided by histological staining and TEM-EDS. Almost all iron in both control and transgenic grains was found in intracellular bodies, indicating symplastic rather than apoplastic transport. Furthermore, a new type of iron body, highly enriched in 57 Fe, was observed in aleurone cells and may represent iron being delivered to phytate globoids. Correlation of the 57 Fe enrichment profiles obtained by NanoSIMS with tissue-specific gene expression provides an updated model of iron homeostasis in cereal grains with relevance for future biofortification strategies.