The effects of deregulation of NR gene expression on growth and nitrogen metabolism of<i>Nicotiana plumbaginifolia</i>plants

Quilleré, Isabelle; Dufossé, Christophe; Roux, Yvette; Foyer, Christine H.; Caboche, Michel; Morot‐Gaudry, Jean‐François

doi:10.1093/jxb/45.9.1205

Cited by 71 publications

(46 citation statements)

References 13 publications

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“…For instance, constitutive expression of NR in C1 plants has previously been found to increase the concentration of total free amino acids . This accumulation of amino acids was mainly due to an increase in Gln levels by a factor of 2 on average Quilleré et al, 1994). The same doubling in Gln concentrations was observed in transgenic tobacco expressing NR under the control of the 35S promoter (Gojon et al, 1998).…”

Section: Discussionsupporting

confidence: 57%

“…All the NR activity detected in these transgenic plants is derived from transgene expression, as the innate NR gene is inactivated by a retrotransposon insertion (Leprince et al, 2001 (Vaucheret et al, 1992). When seedlings had two to three leaves, they were first transferred on sand and grown later in hydroponic conditions in a complete nutrient solution (Quilleré et al, 1994;Lejay et al, 1997) …”

Section: Plant Materialsmentioning

confidence: 99%

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Posttranslational Regulation of Nitrate Reductase Strongly Affects the Levels of Free Amino Acids and Nitrate, whereas Transcriptional Regulation Has Only Minor Influence

et al. 2006

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Diurnal variations in nitrate reductase (NR) activity and nitrogen metabolites were examined in wild-type Nicotiana plumbaginifolia and transformants with various degrees of NR deregulation. In the C1 line, NR was only deregulated at the transcriptional level by placing the NR gene under the control of the cauliflower mosaic virus 35S RNA promoter. In the Del8 and S521D lines, NR was additionally deregulated at the posttranslational level either by a deletion mutation in the N-terminal domain or by a mutation of the regulatory phosphorylation site (serine-521). Posttranslational regulation was essential for pronounced diurnal variations in NR activity. Low nitrate content was related to deregulation of NR, whereas the level of total free amino acids was much higher in plants with fully deregulated NR. Abolishing transcriptional and posttranslational regulation (S521D plants) resulted in an increase of glutamine and asparagine by a factor of 9 and 14, respectively, compared with wild type, whereas abolishing transcriptional regulation (C1 plants) only resulted in increases of glutamine and asparagine by factors ,2. Among the minor amino acids, isoleucine and threonine, in particular, showed enhanced levels in S521D. Nitrate uptake rates were the same in S521D and wild type as determined with 15 N feeding. Deregulation of NR appears to set the level of certain amino acids, whereas diurnal variations were still determined by light/dark. Generally, deregulation of NR at the transcriptional level did not have much influence on metabolite levels, but additional deregulation at the posttranslational level resulted in profound changes of nitrogen metabolite levels.

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Section: Discussionsupporting

confidence: 57%

Section: Plant Materialsmentioning

confidence: 99%

Posttranslational Regulation of Nitrate Reductase Strongly Affects the Levels of Free Amino Acids and Nitrate, whereas Transcriptional Regulation Has Only Minor Influence

et al. 2006

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“…Although overexpression of the high-affinity NRT2.1 (NpNRT2.1) transporter in tobacco (Nicotiana. plumbaginifolia) led to an increase in NO 3 -uptake under low-NO 3 -conditions, no net improvement in NUE was observed (Quilleré et al, 1994).…”

Section: Engineering Nitrogen Use Efficiencymentioning

confidence: 88%

Biotechnology of nutrient uptake and assimilation in plants

et al. 2013

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Plants require a complex balance of mineral nutrients to reproduce successfully. Because the availability of many of these nutrients in the soil is compromised by several factors, such as soil pH, cation presence, and microbial activity, crop plants depend directly on nutrients applied as fertilizers to achieve high yields. However, the excessive use of fertilizers is a major environmental concern due to nutrient leaching that causes water eutrophication and promotes toxic algae blooms. This situation generates the urgent need for crop plants with increased nutrient use efficiency and better-designed fertilization schemes. The plant biology revolution triggered by the development of efficient gene transfer systems for plant cells together with the more recent development of next-generation DNA and RNA sequencing and other omics platforms have advanced considerably our understanding on the molecular basis of plant nutrition and how plants respond to nutritional stress. To date, genes encoding sensors, transcription factors, transporters, and metabolic enzymes have been identified as potential candidates to improve nutrient use efficiency. In addition, the study of other genetic resources, such as bacteria and fungi, allows the identification of alternative mechanisms of nutrient assimilation, which are potentially applicable in plants. Although significant progress in this respect has been achieved by conventional breeding, in this review we focus on the biotechnological approaches reported to date aimed at boosting the use of the three most limiting nutrients in the majority of arable lands: nitrogen, phosphorus, and iron.

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“…Conventional methods of selection have led to the development of varieties able to reduce the absorbed nitrate more efficiently instead of storing it, but these varieties are not able to completely eliminate any risk of toxic accumulation. Studies were therefore undertaken to limit nitrate accumulation by increasing the capacity of a plant to reduce nitrate by increasing nitrate reductase (NR) activity in genetically modified plants, by overexpressing a gene that allows the deregulation of the synthesis of the enzyme [171]. In tobacco a 50% reduction in leaf nitrate content was observed after introduction of the native structural NR gene (Nia2) placed under the control of the 35S strong constitutive promoter.…”

Section: Improvement Of Nitrogen Utilization Using Genetically Modifimentioning

confidence: 99%

Improving Nitrogen Use Efficiency in Crops for Sustainable Agriculture

et al. 2011

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Abstract:In this review, we present the recent developments and future prospects of improving nitrogen use efficiency (NUE) in crops using various complementary approaches. These include conventional breeding and molecular genetics, in addition to alternative farming techniques based on no-till continuous cover cropping cultures and/or organic nitrogen (N) nutrition. Whatever the mode of N fertilization, an increased knowledge of the mechanisms controlling plant N economy is essential for improving NUE and for reducing excessive input of fertilizers, while maintaining an acceptable yield and sufficient profit margin for the farmers. Using plants grown under agronomic conditions, with different tillage conditions, in pure or associated cultures, at low and high N mineral fertilizer input, or using organic fertilization, it is now possible to develop further whole plant agronomic and physiological studies. These can be combined with gene, protein and metabolite profiling to build up a comprehensive picture depicting the different steps of N uptake, assimilation and recycling to produce either biomass in vegetative organs or proteins in storage organs. We provide a critical overview as to how our understanding of the agro-ecophysiological, physiological and molecular controls of N assimilation in crops, under varying environmental conditions, has been improved. We have used combined approaches, based on agronomic studies, whole plant physiology, quantitative genetics, forward and reverse genetics and the emerging systems biology. Long-term sustainability may require a gradual transition from synthetic N inputs to legume-based crop rotation, including continuous cover cropping systems, where these may be possible in certain areas of the world, depending on climatic conditions. Current knowledge and prospects for future agronomic development and application for breeding crops adapted to lower mineral fertilizer input and to alternative farming techniques are explored, whilst taking into account the constraints of both the current world economic situation and the environment.

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The effects of deregulation of NR gene expression on growth and nitrogen metabolism ofNicotiana plumbaginifoliaplants

Cited by 71 publications

References 13 publications

Posttranslational Regulation of Nitrate Reductase Strongly Affects the Levels of Free Amino Acids and Nitrate, whereas Transcriptional Regulation Has Only Minor Influence

Posttranslational Regulation of Nitrate Reductase Strongly Affects the Levels of Free Amino Acids and Nitrate, whereas Transcriptional Regulation Has Only Minor Influence

Biotechnology of nutrient uptake and assimilation in plants

Improving Nitrogen Use Efficiency in Crops for Sustainable Agriculture

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