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Modulating nitrogen flux in sorghum and wheat
Nitrogen is one of the most important nutrients and it is essential for plant growth and development. Cereal crop species such as sorghum (Sorghum bicolor) and wheat (Triticum aestivum) require inputs of nitrogen-based fertilizers in order to maximize yield and plant productivity. Plants have the capacity to assimilate only 50-70% of the nitrogen supplied, resulting in excessive applications while generating a negative environmental impact. Enhancing the capacity of crops to utilize the nitrogen resources more efficiently is essential to ensure food security for the growing population in a sustainable manner. The goal of this research was to assess the effects of the introduction of novel genetic alleles as a means to enhance nitrogen use efficiency in both commodity crops. A series of transgenic events were generated via Agrobacterium-mediated transformation in sorghum and wheat. The first two strategies involved the manipulation of the balance between nitrogen and carbon metabolism. First, a transcription factor from Zea mays, Dof1, was expressed under the control of either the UBI4 or the rbcS1 promoter for constitutive and tissue specific expression. In the second strategy, an Alanine aminotransferase from Hordeum vulgare was delivered into both crops for a constitutive or a root specific expression under the UBI4 or the OsAnt1 controlling elements, respectively. The third strategy reported involved the manipulation of the primary route for inorganic nitrogen assimilation by the constitutive expression of a cytosolic Glutamine synthetase from Oryza sativa in both sorghum and wheat. The results communicated herein indicate that positive agronomic outcomes can be achieved with some of the strategies evaluated. The importance of genes sources, controlling genetic elements and the environmental conditions utilized to evaluate the effects of these technologies, is also highlighted. While positive agronomic outcomes were observed, the agronomic value of these strategies may be realized through an integrated synthetic biology strategy that addresses the process for NUE in a holistic manner.
Agronomy|Molecular biology|Plant sciences
Pena-Perdomo, Pamela Andrea, "Modulating nitrogen flux in sorghum and wheat" (2016). ETD collection for University of Nebraska - Lincoln. AAI10243365.