Engineering nitrogen use efficiency with alanine aminotransferase

2007 ◽  
Vol 85 (3) ◽  
pp. 252-262 ◽  
Author(s):  
Allen G. Good ◽  
Susan J. Johnson ◽  
Mary De Pauw ◽  
Rebecka T. Carroll ◽  
Nic Savidov ◽  
...  

Nitrogen (N) is the most important factor limiting crop productivity worldwide. The ability of plants to acquire N from applied fertilizers is one of the critical steps limiting the efficient use of nitrogen. To improve N use efficiency, genetically modified plants that overexpress alanine aminotransferase (AlaAT) were engineered by introducing a barley AlaAT cDNA driven by a canola root specific promoter (btg26). Compared with wild-type canola, transgenic plants had increased biomass and seed yield both in the laboratory and field under low N conditions, whereas no differences were observed under high N. The transgenics also had increased nitrate influx. These changes resulted in a 40% decrease in the amount of applied nitrogen fertilizer required under field conditions to achieve yields equivalent to wild-type plants.

2020 ◽  
Vol 21 (4) ◽  
pp. 354-367
Author(s):  
Srorlmolook Saeidi ◽  
Seyed Ataollah Siadat ◽  
Ali Moshatati ◽  
محمدرضا Moradi-Telavat ◽  
Niazali Sepahvand ◽  
...  

Botany ◽  
2013 ◽  
Vol 91 (12) ◽  
pp. 866-883 ◽  
Author(s):  
Perrin H. Beatty ◽  
Rebecka T. Carroll ◽  
Ashok K. Shrawat ◽  
David Guevara ◽  
Allen G. Good

Cereal crop plants have low nitrogen (N) use efficiency, taking up only 30% to 50% of the applied N fertilizers, with the rest having the potential for loss into the environment as N pollution. One way to address this problem is to improve the nitrogen use efficiency of cereal crops using a transgenic approach. We developed alanine aminotransferase overexpressing rice, and we have previously determined that this modification provided an improved nitrogen-use phenotype to the engineered plants. In this study, the transgenic rice were grown in low, medium, and high nitrogen supply, and morphology, plant N levels, enzymatic activity, metabolite levels, and transcriptome response in the roots and shoots at active and maximum tillering at each N level were measured. The transcriptome response was analysed further using MapMan and PageMan to view multiple comparisons. The transgenic rice plants showed improved nitrogen use efficiency at medium and high N supply, but with few significant changes to the amino acid levels or to the transcriptome. The transgenic plants grown in high N showed up-regulation of transcripts associated with photosynthesis, non-melavonate pathway secondary metabolites, protein degradation, and many unknown function transcripts.


2022 ◽  
Vol 278 ◽  
pp. 108430
Author(s):  
Olusegun Idowu ◽  
Yuanzheng Wang ◽  
Koki Homma ◽  
Tetsuya Nakazaki ◽  
Zhengjin Xu ◽  
...  

2014 ◽  
Vol 94 (6) ◽  
pp. 1009-1012 ◽  
Author(s):  
David R. Guevara ◽  
Yong-Mei Bi ◽  
Steven J. Rothstein

Guevara, D. R., Bi, Y.-M. and Rothstein, S. J. 2014. Identification of regulatory genes to improve nitrogen use efficiency. Can. J. Plant Sci. 94: 1009–1012. Crop production on soils containing sub-optimal levels of nitrogen (N) severely compromises yield potential. The development of crop varieties displaying high N use efficiency (NUE) is necessary in order to optimize N fertilizer use, and reduce the environmental damage caused by the current excessive application of N in agricultural areas. Genome-wide microarray analysis of rice plants grown under N-limiting environments was performed to identify NUE candidate genes. An early nodulin gene, OsENOD93-1, was strongly up-regulated during plant growth under low N. A constitutive Ubiquitin promoter was used to drive the expression of the OsENOD93-1 gene in transgenic plants to determine the importance of OsENOD93-1 for rice NUE. Transgenic rice plants over-expressing the OsENOD93-1 gene achieved ∼23% and 16% more yield and biomass, respectively, compared with wild-type plants when grown under N-limitation conditions. OsENOD93-1-OX transgenic plants accumulated a higher amount of total amino acids in the roots and xylem sap under N stress, suggesting that OsENOD93-1 plays a role in the transportation of amino acids. Taken together, we demonstrate that an effective way to identify NUE gene candidates involves both transcriptional profiling coupled with a transgenic validation approach to improve complex traits such as NUE in important crops.


2020 ◽  
Author(s):  
Jie Wu ◽  
Zi-Sheng Zhang ◽  
Jing-Qiu Xia ◽  
Alamin Alfatih ◽  
Ying Song ◽  
...  

AbstractNitrogen (N) is one of the key essential macronutrients that affects rice growth and yield. Inorganic N fertilizers are excessively used to boost yield and generate serious collateral environmental pollution. Therefore, improving crop N use efficiency (NUE) is highly desirable and has been a major endeavor in crop improvement. However, only a few regulators have been identified that can be used to improve NUE in rice to date. Here we show that the NIN-like protein OsNLP4 significantly improves the rice NUE and yield. Field trials consistently showed that loss-of-OsNLP4 dramatically reduced yield and NUE compared with wild type under different N regimes. In contrast, the OsNLP4 overexpression lines remarkably increased yield by 30% and NUE by 47% under moderate N level compared with wild type. Transcriptomic analyses revealed that OsNLP4 orchestrates the expression of a majority of known N uptake, assimilation and signaling genes by directly binding to the nitrate-responsive cis-element in their promoters to regulate their expression. Moreover, overexpression of OsNLP4 can recover the phenotype of Arabidopsis nlp7 mutant and enhance its biomass. Our results demonstrate that OsNLP4 is a master regulator of NUE in rice and sheds light on crop NUE improvement.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Zhen Zhang ◽  
Yongli Zhang ◽  
Yu Shi ◽  
Zhenwen Yu

AbstractThis study aims to investigate optimization of the basal-top-dressing nitrogen ratio for improving winter wheat grain yield, nitrogen use efficiency, water use efficiency and physiological parameters under supplemental irrigation. A water-saving irrigation (SI) regime was established and sufficient irrigation (UI) was used as a control condition. The split-nitrogen regimes used were based on a identical total nitrogen application rate of 240 kg ha−1 but were split in four different proportions between sowing and the jointing stage; i.e. 10:0 (N1), 7:3 (N2), 5:5 (N3) and 3:7 (N4). Compared with the N1, N2 and N4 treatments, N3 treatment increased grain yield, nitrogen and water use efficiencies by 5.27–17.75%, 5.68–18.78% and 5.65–31.02%, respectively, in both years. The yield advantage obtained with the optimized split-nitrogen fertilizer application may be attributable to greater flag leaf photosynthetic capacity and grain-filling capacity. Furthermore, the N3 treatment maintained the highest nitrogen and water use efficiencies. Moreover, we observed that water use efficiency of SI compared with UI increased by 9.75% in 2016 and 10.79% in 2017, respectively. It can be concluded that SI along with a 5:5 basal-top-dressing nitrogen ratio should be considered as an optimal fertigation strategy for both high grain yield and efficiency in winter wheat.


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