Sakakibara Hitoshi
Plant Science Center, RIKEN (The Institute of Physical and Chemical Research), 1-7-22 Suehiro, Tsurumi, Yokohama 230-0045, Japan.
J Plant Res. 2003 Jun;116(3):253-7. doi: 10.1007/s10265-003-0097-3. Epub 2003 Apr 17.
Inorganic nitrogen is a limiting factor in plant growth and development. Plants constantly sense changes in nitrogen availability and respond appropriately by modulating gene expression. Plants employ multiple routes for the long-distance signaling and communication of nitrogen status. One of these depends on nitrate itself (nitrate-specific signaling), while another uses cytokinin as a messenger. Recent studies suggest that nitrate-specific signaling functions predominantly in the context of the synthesis of amino acids and nucleic acids. This pathway includes the control of the expression of a wide variety of genes. On the other hand, cytokinin-mediated signaling is related mainly to the control of nitrogen partitioning and development. Nitrogen-dependent cytokinin accumulation and the involvement of His-Asp phosphorelay systems are characteristic of this pathway. The coordination of both regulatory pathways seems to be crucially important for the integration of nitrogen signals at the whole plant level.
无机氮是植物生长发育的限制因素。植物不断感知氮素可利用性的变化，并通过调节基因表达做出适当反应。植物采用多种途径进行氮素状态的长距离信号传递和交流。其中之一依赖于硝酸盐本身（硝酸盐特异性信号传导），而另一种则使用细胞分裂素作为信使。最近的研究表明，硝酸盐特异性信号传导主要在氨基酸和核酸合成的背景下起作用。该途径包括对多种基因表达的控制。另一方面，细胞分裂素介导的信号传导主要与氮素分配和发育的控制有关。氮依赖性细胞分裂素积累和组氨酸-天冬氨酸磷酸中继系统的参与是该途径的特征。这两种调节途径的协调对于在整个植物水平上整合氮信号似乎至关重要。
