A crucial role for a node‐localized transporter, HvSPDT, in?loading phosphorus into barley grains
A crucial role for a node‐localized transporter, HvSPDT, in?loading phosphorus into barley grains
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节点局部转运蛋白 HvSPDT 在将磷装载到大麦籽粒中的关键作用
DOI：
10.1111/nph.18057
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发表时间：
2022
期刊：
影响因子：
9.4
通讯作者：
Ma Jian Feng
中科院分区：
文献类型：
--
作者：
Gu Mian;Huang Hengliang;Hisano Hiroshi;Ding Guangda;Huang Sheng;Mitani‐Ueno Namiki;Yokosho Kengo;Sato Kazuhiro;Yamaji Naoki;Ma Jian Feng
籽粒是禾谷类作物磷素的主要库，占植物磷素总量的60-85%，但磷素进入籽粒的机制尚不清楚，我们对大麦（Hordeum vulgare）中磷素分配所需的转运蛋白基因HvSPDT（SULTR‐like phosphorus distribution transporter）进行了功能鉴定，HvSPDT编码一种质膜定位的Pi/H+共转运蛋白。在营养生长期和生殖生长期，它主要表达于节中。此外，它的表达诱导无机磷（Pi）缺乏。在节中，HvSPDT在膨大和弥漫的维管束的木质部和韧皮部区域中表达。在低磷条件下，HvSPDT基因敲除降低了营养生长期叶片中磷向新叶的分配，但增加了向老叶的分配。然而，敲除HvSPDT并没有改变P从老年器官向年轻器官的再分配。在生殖生长阶段，HvSPDT基因敲除显著降低了P向籽粒的分配，导致籽粒产量显著降低，特别是在磷限制条件下，这表明基于节位的HvSPDT基因通过优先分配木质部和韧皮部中的P而在大麦籽粒中起着重要作用。
Grains are the major sink of phosphorus (P) in cereal crops, accounting for 60–85% of total plant P, but the mechanisms underlying P loading into the grains are poorly understood.We functionally characterized a transporter gene required for the distribution of P to the grains in barley (Hordeum vulgare),HvSPDT(SULTR‐like phosphorus distribution transporter).HvSPDTencoded a plasma membrane‐localized Pi/H+cotransporter. It was mainly expressed in the nodes at both the vegetative and reproductive stages. Furthermore, its expression was induced by inorganic phosphate (Pi) deficiency. In the nodes,HvSPDTwas expressed in both the xylem and phloem region of enlarged and diffuse vascular bundles. Knockout ofHvSPDTdecreased the distribution of P to new leaves, but increased the distribution to old leaves at the vegetative growth stage under low P supply. However, knockout ofHvSPDTdid not alter the redistribution of P from old to young organs. At the reproductive stage, knockout ofHvSPDTsignificantly decreased P allocation to the grains, resulting in a considerable reduction in grain yield, especially under P‐limited conditions.Our results indicate that node‐based HvSPDT plays a crucial role in loading P into barley grains through preferentially distributing P from the xylem and further to the phloem.