Plays Key Roles in Plant Architecture and Yield Response to Nitrogen Fertilizer in Wheat.

Understanding the molecular mechanisms in wheat response to nitrogen (N) fertilizer will help us to breed wheat varieties with improved yield and N use efficiency. Here, we cloned , , and , which were upregulated in roots and shoots of wheat by low N availability. In a hydroponic culture, lateral root length and N uptake were decreased in both overexpression and knockdown of at the seedling stage. In the field experiment with normal N supply, the grain yield of overexpression of is significantly reduced (14.5%), and the knockdown of was significantly reduced (15.5%). The grain number per spike of overexpression of was significantly increased (7.2%), but the spike number was significantly reduced (19.2%) compared with wild type (WT), although the grain number per spike of knockdown of was significantly decreased (15.3%), with no difference in the spike number compared with WT. Combined with the agronomic data from the field experiment of normal N and low N, both overexpression and knockdown of inhibited yield response to N fertilizer. Overexpressing greatly increased grain N concentration with no significant detrimental effect on grain yield under low N conditions; TaLAMP1-3 is therefore valuable in engineering wheat for low input agriculture. These results suggested that is critical for wheat adaptation to N availability and in shaping plant architecture by regulating spike number per plant and grain number per spike. Optimizing expression may facilitate wheat breeding with improved yield, grain N concentration, and yield responses to N fertilizer.