Details

Autor(en) / Beteiligte

• Chen, Xiangbin
• Yao, Qinfang
• Gao, Xiuhua
• Jiang, Caifu
• Harberd, Nicholas P.
• Fu, Xiangdong

Titel

Shoot-to-Root Mobile Transcription Factor HY5 Coordinates Plant Carbon and Nitrogen Acquisition

Ist Teil von

• Current biology, 2016-03, Vol.26 (5), p.640-646

Ort / Verlag

England: Elsevier Ltd

Erscheinungsjahr

2016

Link zum Volltext

Quelle

Access via ScienceDirect (Elsevier)

Beschreibungen/Notizen

• 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. [Display omitted] •HY5 is essential for light-responsive coordination of the growth of shoots and roots•Shoot-to-root translocated HY5 mediate light-activated root growth and N uptake•Carbohydrate photosynthate-induced NRT2.1 expression and N uptake depend upon HY5•HY5 contributes to maintain balance of C and N metabolism at varying light fluence Chen et al. show that transcription factor HY5 is a shoot-to-root mobile signal that mediates light-responsive coupling of shoot growth and C assimilation with root growth and N uptake in Arabidopsis. HY5 mobility thus contributes to maintain homeostatic balance between whole-plant C and N metabolism in response to a fluctuating environment.