Loss of OPT3 function decreases phloem copper levels and impairs crosstalk between copper and iron homeostasis and shoot-to-root signaling in Arabidopsis thaliana
Loss of OPT3 function decreases phloem copper levels and impairs crosstalk between copper and iron homeostasis and shoot-to-root signaling in Arabidopsis thaliana
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DOI：
10.1093/plcell/koad053
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发表时间：
2023-03-18
期刊：
影响因子：
11.6
通讯作者：
Vatamaniuk, Olena K.
中科院分区：
文献类型：
--
作者：
Chia, Ju-Chen;Yan, Jiapei;Vatamaniuk, Olena K.
拟南芥OPT 3将Cu和Fe装载到韧皮部伴随细胞中，用于分配到库组织和系统地传递Cu和Fe缺乏的信号。因此，它们被根部吸收是受到严格调控的。虽然植物的感觉和响应本地铜的可用性，系统的铜吸收的调节还没有记录在本地和系统控制铁的吸收。韧皮部中的铁丰度已被建议系统地起作用，调节根中的铁吸收基因的表达。一致地，在缺乏韧皮部伴随细胞定位的铁转运蛋白寡肽转运蛋白3（AtOPT 3）的拟南芥突变体中，茎到根的铁信号传导被破坏。我们报告说，AtOPT 3也运输铜在异源系统，并有助于其交付从源到汇在植物。opt 3突变体含有较少的铜在韧皮部，是敏感的铜缺乏和安装在根和幼叶转录铜缺乏反应。通过叶片韧皮部向opt 3突变体和缺铜或缺铁的野生型幼苗中添加铜或铁，可下调根中缺铜和缺铁标记基因的表达。这些数据表明存在茎-根Cu信号传导，突出了Cu/Fe相互作用的复杂性，以及AtOPT 3在微调植物Cu和Fe需求的根转录响应中的作用。
Arabidopsis OPT3 loads Cu and Fe into phloem companion cells for distribution to sink tissues and systemic signaling of Cu and Fe deficiencies.Copper (Cu) and iron (Fe) are essential micronutrients that are toxic when accumulating in excess in cells. Thus, their uptake by roots is tightly regulated. While plants sense and respond to local Cu availability, the systemic regulation of Cu uptake has not been documented in contrast to local and systemic control of Fe uptake. Fe abundance in the phloem has been suggested to act systemically, regulating the expression of Fe uptake genes in roots. Consistently, shoot-to-root Fe signaling is disrupted in Arabidopsis thaliana mutants lacking the phloem companion cell-localized Fe transporter, OLIGOPEPTIDE TRANSPORTER 3 (AtOPT3). We report that AtOPT3 also transports Cu in heterologous systems and contributes to its delivery from sources to sinks in planta. The opt3 mutant contained less Cu in the phloem, was sensitive to Cu deficiency and mounted a transcriptional Cu deficiency response in roots and young leaves. Feeding the opt3 mutant and Cu- or Fe-deficient wild-type seedlings with Cu or Fe via the phloem in leaves downregulated the expression of both Cu- and Fe-deficiency marker genes in roots. These data suggest the existence of shoot-to-root Cu signaling, highlight the complexity of Cu/Fe interactions, and the role of AtOPT3 in fine-tuning root transcriptional responses to the plant Cu and Fe needs.