The sugar transporter ZmSUGCAR1 of the nitrate transporter 1/peptide transporter family is critical for maize grain filling
The sugar transporter ZmSUGCAR1 of the nitrate transporter 1/peptide transporter family is critical for maize grain filling
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DOI：
10.1093/plcell/koac256
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发表时间：
2022-09-01
期刊：
影响因子：
11.6
通讯作者：
Lai, Jinsheng
中科院分区：
文献类型：
--
作者：
Yang, Bo;Wang, Jing;Lai, Jinsheng
母体向子代的营养转移对籽粒发育和产量至关重要。硝酸盐转运蛋白1/肽转运蛋白（NRT1-PTR）型转运蛋白通常转运硝酸盐、肽和离子。在这里，我们报告的鉴定玉米（玉米）NRT1-PTR型转运蛋白，转运蔗糖和葡萄糖。本文采用示踪剂标记的糖摄取和一系列电生理研究方法，包括非洲爪蟾卵母细胞的双电极电压钳、无创微电极离子流测定和HEK293T细胞的膜片钳，系统地验证了这种糖转运蛋白的活性，命名为Sucrose and Glucose Carrier 1（SUGCAR 1）。ZmSUGCAR 1在胚乳基部转移层特异性表达，ZmSUGCAR 1功能缺失突变导致玉米籽粒蔗糖和葡萄糖含量显著降低，籽粒皱缩。值得注意的是，ZmSUGCAR 1直系同源物SbSUGCAR 1（来自两色高粱）和TaSUGCAR 1（来自小麦）在卵母细胞中显示出相似的糖转运活性，支持SUGCAR 1在密切相关的谷类物种中的功能保守性。因此，ZmSUGCAR 1的发现揭示了一种对谷物发育至关重要的糖转运蛋白，并为玉米和其他粮食作物种子灌浆和产量的遗传改良开辟了潜在途径。玉米蔗糖和葡萄糖载体1（ZmSUGCAR 1）编码一种在籽粒灌浆中发挥作用的糖转运蛋白。
Maternal-to-filial nutrition transfer is central to grain development and yield. nitrate transporter 1/peptide transporter (NRT1-PTR)-type transporters typically transport nitrate, peptides, and ions. Here, we report the identification of a maize (Zea mays) NRT1-PTR-type transporter that transports sucrose and glucose. The activity of this sugar transporter, named Sucrose and Glucose Carrier 1 (SUGCAR1), was systematically verified by tracer-labeled sugar uptake and serial electrophysiological studies including two-electrode voltage-clamp, non-invasive microelectrode ion flux estimation assays in Xenopus laevis oocytes and patch clamping in HEK293T cells. ZmSUGCAR1 is specifically expressed in the basal endosperm transfer layer and loss-of-function mutation of ZmSUGCAR1 caused significantly decreased sucrose and glucose contents and subsequent shrinkage of maize kernels. Notably, the ZmSUGCAR1 orthologs SbSUGCAR1 (from Sorghum bicolor) and TaSUGCAR1 (from Triticum aestivum) displayed similar sugar transport activities in oocytes, supporting the functional conservation of SUGCAR1 in closely related cereal species. Thus, the discovery of ZmSUGCAR1 uncovers a type of sugar transporter essential for grain development and opens potential avenues for genetic improvement of seed-filling and yield in maize and other grain crops.Zea mays Sucrose and Glucose Carrier1 (ZmSUGCAR1) encodes a sugar transporter that functions in grain filling.