Nitrogen fixation and assimilation

Abstract

New crop plants suited to grow in semiarid environments will be fundamental to the future of agriculture. The interactions between nitrogen supply and water availability that determine yield and quality in crops grown in semiarid environments are being elucidated. Tools for analyzing the metabolic changes associated with enhanced nitrogen assimilation under drought have been generated. Here is summarized the crop and other plants that have altered NUE, yield performances, and metabolic profiles caused by in planta expression of 31 different transgenes generated in the past two decades. The change in nitrogen concentration has profound effects on plant metabolisms. The metabolic changes resulted in phenotypic changes that included increases in mean plant biomass production in dry soils, tolerance to the herbicide phosphinothricin, tolerance to both severe and mild water deficit, and resistance to rotting necrotrophs. Leaves, and grain had higher nutritional value and higher yield, indicating improved NUE and WUE by some of the transgenes. Therefore, in view of global climate change, continued efforts to alter nitrogen fixation and assimilation by transgenesis and mutation should be pursued through technology stacking.