Shoot-to-Root Mobile Transcription Factor HY5 Coordinates Plant Carbon and Nitrogen Acquisition
Shoot-to-Root Mobile Transcription Factor HY5 Coordinates Plant Carbon and Nitrogen Acquisition
复制标题
从芽到根的移动转录因子 HY5 协调植物碳和氮的获取
DOI：
10.1016/j.cub.2015.12.066
复制
发表时间：
2016-03-07
期刊：
影响因子：
9.2
通讯作者：
Fu, Xiangdong
中科院分区：
文献类型：
--
作者：
Chen, Xiangbin;Yao, Qinfang;Fu, Xiangdong
地上部光合固碳与根系无机氮吸收的协调优化了植物在波动环境中的表现[1]。然而，这种长距离的茎-根协调的分子基础却知之甚少。在这里，我们表明，拟南芥伸长下胚轴5（HY 5），一个bZIP转录因子，调节生长响应光[2，3]，是一个茎到根移动的信号，介导光促进根生长和硝酸盐吸收。茎源HY 5自动激活根HY 5，并通过激活NRT2.1（一种编码高亲和力硝酸盐转运蛋白的基因）促进根硝酸盐吸收[4]。在地上部，HY 5促进碳同化和转运，而在根中，HY 5激活NRT2.1的表达和硝酸盐的吸收是加强增加碳同化物（蔗糖）水平。我们进一步表明，HY 5的功能是通量率调制，使稳态维持碳氮平衡在不同的光环境。因此，移动的HY 5协调光响应的碳和氮代谢，并因此芽和根的生长，在整个生物体响应环境光波动。
Coordination of shoot photosynthetic carbon fixation with root inorganic nitrogen uptake optimizes plant performance in a fluctuating environment [1]. However, the molecular basis of this long-distance shoot-root coordination is little understood. Here we show that Arabidopsis ELONGATED HYPOCOTYL5 (HY5), a bZIP transcription factor that regulates growth in response to light [2, 3], is a shoot-to-root mobile signal that mediates light promotion of root growth and nitrate uptake. Shoot-derived HY5 auto-activates root HY5 and also promotes root nitrate uptake by activating NRT2.1, a gene encoding a high-affinity nitrate transporter [4]. In the shoot, HY5 promotes carbon assimilation and translocation, whereas in the root, HY5 activation of NRT2.1 expression and nitrate uptake is potentiated by increased carbon photoassimilate (sucrose) levels. We further show that HY5 function is fluence-rate modulated and enables homeostatic maintenance of carbon-nitrogen balance in different light environments. Thus, mobile HY5 coordinates light-responsive carbon and nitrogen metabolism, and hence shoot and root growth, in a whole-organismal response to ambient light fluctuations.