Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki 710-0046, Japan.
Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki 710-0046, Japan.
Curr Opin Plant Biol. 2017 Oct;39:18-24. doi: 10.1016/j.pbi.2017.05.002. Epub 2017 May 27.
Mineral elements taken up by the roots will be delivered to different organs and tissues depending on their requirements. In Poaceae, this selective distribution is mainly mediated in the nodes, which have highly developed and fully organized vascular systems. Inter-vascular transfer of mineral elements from enlarged vascular bundles to diffuse vascular bundles is required for their preferential distribution to developing tissues and reproductive organs. A number of transporters involved in this inter-vascular transfer processes have been identified mainly in rice. They are localized at the different cell layers and form an efficient machinery within the node. Furthermore, some these transporters show rapid response to the environmental changes of mineral elements at the protein level. In addition to the node-based transporters, distinct nodal structures including enlarged xylem area, folded plasma membrane of xylem transfer cells and presence of an apoplastic barrier are also required for the efficient inter-vascular transfer. Manipulation of node-based transporters will provide a novel breeding target to improve nutrient use efficiency, productivity, nutritional value and safety in cereal crops.
根系吸收的矿物质元素将根据它们的需求被输送到不同的器官和组织。在禾本科植物中，这种选择性分布主要在节点中进行介导，节点具有高度发达和完全组织化的脉管系统。为了将矿物质元素优先分配到发育组织和生殖器官，需要从增大的维管束向弥散的维管束进行脉管间的矿物质元素转移。已经在水稻中主要鉴定出了一些参与这种脉管间转移过程的转运蛋白。它们定位于不同的细胞层，并在节点内形成有效的机制。此外，其中一些转运蛋白在蛋白质水平上对矿物质元素的环境变化表现出快速的响应。除了基于节点的转运蛋白外，高效的脉管间转移还需要包括增大的木质部区域、木质部转移细胞的折叠质膜和质外体屏障在内的独特节点结构。对基于节点的转运蛋白的操作将为改善谷类作物的养分利用效率、生产力、营养价值和安全性提供一个新的育种目标。
