PP ：林金星IAA流成果丨NRT1.1磷酸化调节侧根发育的机制（附NMT实验体系）

期刊：Plant Physiology

主题：NRT1.1磷酸化调节侧根发育的机制

标题：Phosphorylation-mediated dynamics of nitrate  transceptor NRT1.1 regulate auxin flux and nitrate signaling in lateral  root growth

影响因子：6.305

检测指标：IAA流速

检测部位：酵母细胞

IAA流速流实验处理方法：

转化酵母细胞在SD-URA培养基长到对数期，转至SG-URA培养基[SD-URA培养基中的dextrose替换为2%（m/v）galactose]上，培养24-48小时，诱导NRT1.1，T101A，T101D，mRuby表达。离心收集并制成SG-URA悬液。

IAA流速流实验测试液成份：

0.5 μM IAA, 2% (m/v) galactose, 0.3 mM MES, pH 5.8

作者：北京林业大学单晓昳、林金星、张曦

英文摘要

The dual-affinity nitrate transceptor NITRATE  TRANSPORTER 1.1 (NRT1.1) has two modes of transport and signaling,  governed by threonine101 (T101) phosphorylation. NRT1.1 regulates  lateral root (LR) development by modulating nitrate-dependent basipetal  auxin export and nitrate-mediated signal transduction.

Here,  using the Arabidopsis thaliana NRT1.1T101D phosphomimetic and  NRT1.1T101A non-phosphorylatable mutants, we found that the  phosphorylation state of NRT1.1 plays a key role in NRT1.1 function  during LR development. Single-particle tracking revealed that  phosphorylation affected NRT1.1 spatiotemporal dynamics. The  phosphomimetic NRT1.1T101D form showed fast lateral mobility and  membrane partitioning that facilitated auxin flux under low-nitrate  conditions.

By contrast, non-phosphorylatable NRT1.1T101A showed  low lateral mobility and oligomerized at the plasma membrane (PM), where  it induced endocytosis via the clathrin-mediated endocytosis and  microdomain-mediated endocytosis pathways under high-nitrate conditions.

These  behaviors promoted LR development by suppressing NRT1.1-controlled  auxin transport on the PM and stimulating Ca2+-ARABIDOPSIS NITRATE  REGULATED 1 (ANR1) signaling from the endosome.

中文摘要（谷歌机翻）

双亲和**盐转运蛋白NITRATE TRANSPORTER 1.1（NRT1.1）具有两种运输和信号传导模式，由苏氨酸101（T101）磷酸化控制。 NRT1.1通过调节**盐依赖性碱基生长素输出和**盐介导的信号转导来调节侧根（LR）发育。

在这里，使用拟南芥NRT1.1T101D磷酸化和NRT1.1T101A非磷酸化突变体，我们发现NRT1.1的磷酸化状态在LR发育期间在NRT1.1功能中起关键作用。单粒子追踪显示磷酸化影响NRT1.1时空动态。磷酸化模拟NRT1.1T101D形式显示出快速的侧向移动性和膜分配，其促进了在低**盐条件下的生长素通量。

相比之下，不可磷酸化的NRT1.1T101A显示出低的侧向迁移率并且在质膜（PM）处寡聚化，其在高**盐条件下通过网格蛋白介导的内吞作用和微区介导的胞吞作用途径诱导内吞作用。

这些行为通过抑制PM上的NRT1.1控制的生长素转运并刺激来自内体的Ca2 + -ARABIDOPSIS**盐调节1（ANR1）信号传导来促进LR发展。