A citrate efflux transporter important for manganese distribution and phosphorus uptake in rice.
A citrate efflux transporter important for manganese distribution and phosphorus uptake in rice.
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DOI：
10.1111/tpj.16463
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发表时间：
2023-09
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影响因子：
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通讯作者：
Poonam Panchal;Chitra Bhatia;Yi Chen;Meenakshi Sharma;Jyoti Bhadouria;Lokesh Verma;Kanika Maurya;Anthony J Miller;J. Giri
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作者：
Poonam Panchal;Chitra Bhatia;Yi Chen;Meenakshi Sharma;Jyoti Bhadouria;Lokesh Verma;Kanika Maurya;Anthony J Miller;J. Giri
植物柠檬酸转运蛋白具有矿质营养吸收和动态平衡的功能，通常属于多种药物和有毒化合物挤出转运蛋白家族。我们鉴定并鉴定了水稻柠檬酸转运蛋白OsCT1，它不同于已知的植物柠檬酸转运蛋白，在结构上与水稻硅转运蛋白相似。结构域分析表明，OsCT1携带细菌柠檬酸-金属转运蛋白结构域CitMHS。在非洲爪哇卵母细胞中表达的OsCT1具有柠檬酸外排活性，并定位于细胞膜。它在水稻的枝条和生殖组织中高度表达，其启动子活性在维管系统周围的细胞中可见。OsCT1基因敲除品系(KO)地上部和根分泌物中柠檬酸含量降低，而过表达(OE)品系根中柠檬酸分泌量较高。此外，KO和OE品系表现出锰(Mn)分布的变异，导致其农艺性状的变化。在缺锰条件下，KO品系向新叶的锰供应受阻(先进行8天的0μm MnCl2·4H2O处理)。磷的分配没有显著差异，但营养生长期KO的磷吸收减少，OE的磷吸收增加。此外，在非洲爪哇卵母细胞上的实验表明，OsCT1可以将柠檬酸与锰一起外排。通过这种方式，我们对植物中柠檬酸盐-金属运输的机制及其在矿物质动态平衡中的作用提供了见解，矿物质动态平衡与细菌同行保持保守。
The plant citrate transporters, functional in mineral nutrient uptake and homeostasis, usually belong to the multidrug and toxic compound extrusion transporter family. We identified and functionally characterized a rice (Oryza sativa) citrate transporter, OsCT1, which differs from known plant citrate transporters and is structurally close to rice silicon transporters. Domain analysis depicted that OsCT1 carries a bacterial citrate-metal transporter domain, CitMHS. OsCT1 showed citrate efflux activity when expressed in Xenopus laevis oocytes and is localized to the cell plasma membrane. It is highly expressed in the shoot and reproductive tissues of rice, and its promoter activity was visible in cells surrounding the vasculature. The OsCT1 knockout (KO) lines showed a reduced citrate content in the shoots and the root exudates, whereas overexpression (OE) line showed higher citrate exudation from their roots. Further, the KO and OE lines showed variations in the manganese (Mn) distribution leading to changes in their agronomical traits. Under deficient conditions (Mn-sufficient conditions followed by 8 days of 0 μm MnCl2 · 4H2 O treatment), the supply of manganese towards the newer leaf was found to be obstructed in the KO line. There were no significant differences in phosphorus (P) distribution; however, P uptake was reduced in the KO and increased in OE lines at the vegetative stage. Further, experiments in Xenopus oocytes revealed that OsCT1 could efflux citrate with Mn. In this way, we provide insights into a mechanism of citrate-metal transport in plants and its role in mineral homeostasis, which remains conserved with their bacterial counterparts.