Light Regulation of Nitrate uptake, Assimilation and Metabolism

Lillo, Cathrine

doi:10.1007/978-1-4020-2728-4_6

Cited by 23 publications

(14 citation statements)

References 146 publications

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“…In darkened leaves, or root tissue, reducing power for NiR and GOGAT must be generated by other means than photosynthesis, but still involves ferredoxin or a ferredoxin-like protein (Meyer and Stitt 2001). Rapid down-regulation of NR due to, for instance, a sudden decrease in light intensity has been claimed to be necessary to avoid accumulation of nitrite, which is toxic to the plant (Riens and Heldt 1992;Huber et al 2002;Lillo 2004), and the work presented here indeed demonstrates that the Ser 521 can be important for cessation of nitrite production.…”

Section: Introductionmentioning

confidence: 98%

Mutation of the regulatory phosphorylation site of tobacco nitrate reductase results in high nitrite excretion and NO emission from leaf and root tissue

Lea

Hoopen

Provan

et al. 2004

Planta

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In wild-type Nicotiana plumbaginifolia Viv. and other higher plants, nitrate reductase (NR) is regulated at the post-translational level and is rapidly inactivated in response to, for example, a light-to-dark transition. This inactivation is caused by phosphorylation of a conserved regulatory serine residue, Ser 521 in tobacco, and interaction with divalent cations or polyamines, and 14-3-3 proteins. The physiological importance of the post-translational NR modulation is presently under investigation using a transgenic N. plumbaginifolia line. This line expresses a mutated tobacco NR where Ser 521 has been changed into aspartic acid (Asp) by site-directed mutagenesis, resulting in a permanently active NR enzyme. When cut leaves or roots of this line (S(521)) were placed in darkness in a buffer containing 50 mM KNO(3), nitrite was excreted from the tissue at rates of 0.08-0.2 micromol (g FW)(-1) h(-1) for at least 5 h. For the control transgenic plant (C1), which had the regulatory serine of NR intact, nitrite excretion was low and halted completely after 1-3 h. Without nitrate in the buffer in which the tissue was immersed, nitrite excretion was also low for S(521), although 20-40 micromol (g FW)(-1) nitrate was present inside the tissue. Apparently, stored nitrate was not readily available for reduction in darkness. Leaf tissue and root segments of S(521) also emitted much more nitric oxide (NO) than the control. Importantly, NO emission from leaf tissue of S(521) was higher in the dark than in the light, opposite to what was usually observed when post-translational NR modulation was operating.

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Section: Introductionmentioning

confidence: 98%

Mutation of the regulatory phosphorylation site of tobacco nitrate reductase results in high nitrite excretion and NO emission from leaf and root tissue

Lea

Hoopen

Provan

et al. 2004

Planta

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“…Although NR is in the cytosol, the product of the NR reaction, nitrite, which is toxic, is further reduced and assimilated in the chloroplasts. Nitrite reductase in the chloroplasts and NR in the cytosol are usually found to be co-regulated (Lillo 2004), and NR can, therefore, be expected to be induced as part of the deetiolation process and development of chloroplasts.…”

Section: Introductionmentioning

confidence: 99%

“…Both light acting through photosynthesis giving rise to sugars or other products, and light absorbed through the phytochrome system is known to increase the expression of nitrate reductase (Appenroth et al 2000;Lillo 2004;Lea et al 2006). Phytochromes are light receptors involved in regulation of important processes like germination, de-etiolation, shade avoidance, circadian rhythms and Xowering.…”

Section: Introductionmentioning

confidence: 99%

HY5 and HYH are positive regulators of nitrate reductase in seedlings and rosette stage plants

Jonassen

Lea

Lillo

2007

Planta

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HY5 and HYH are bZIP transcription factors well known to be involved in photomorphogenesis and light signalling. Loss-of-function mutants of HY5 and HYH revealed that these genes are essential for induction of a key enzyme in nitrogen assimilation, nitrate reductase (EC 1.7.1.1). In Arabidopsis thaliana seedlings nitrate reductase was expressed under low irradiance far-red or red light at the same level as under higher irradiance, photosynthetic active, white light. However, high NR expression at low light levels occurred only in the presence of sucrose in the growth medium. Sucrose did not promote expression in darkness. Whereas HY5 was necessary for high nitrate reductase expression in far-red light, HYH was important in red light. COP1 is known to promote degradation of HY5 and HYH, and in the cop1 mutant, nitrate reductase activity was relatively high also in darkness. PhyA and PhyB mutants were tested, and confirmed the phytochrome dependency for far-red and red light induction of nitrate reductase in seedlings. In rosette leaves of 3-week-old green plants the daily increase in nitrate reductase expression in response to light-on was abolished in the hyh and hy5 hyh double mutant. The hy5 hyh double mutant had lower nitrate reductase activity than any of the single mutants in photosynthetic active light in both seedlings and rosette leaves.

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“…Both drought and heat stresses together affect N availability storage and remobilization in pine trees (Rennenberg et al 2009 ;Huang et al 2012 ). The activity of many nitrate-regulated genes is hypothesized to be regulated by light, and evidence shows that both NRT2 and NR activity is dependent on light as well as nitrogen (Lillo 2004(Lillo , 2008Chapman and Miller 2011 ). Thus, mounting evidence suggests that the effect of various abiotic stresses can lead to unanticipated changes in plant growth and development.…”

Section: N In Multiple Interacting Stressesmentioning

confidence: 97%

Nitrogen and Stress

Jangam

Raghuram

2015

Elucidation of Abiotic Stress Signaling in Plants

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Nitrogen is an essential macronutrient for the plants and fertilizer N-use effi ciency is becoming an increasing economic and environmental concern. The nutrient stress conditions of N defi ciency and N excess may get exacerbated by other abiotic stresses, which in turn are likely to be worsened by climate change. Exploring their interrelationships is being increasingly facilitated by the growing knowledge of the genome-wide N response as well as other abiotic stress responses in model plants. Nitrate and its more reduced forms are not only sources of plant N nutrition but also signals that govern their own uptake; N, C, and redox metabolism; and hormonal and other organism-wide responses. The signaling mechanisms involved in N response or response to N stress or N-use effi ciency are currently far less well understood than those in other abiotic stresses. The purpose of this review is to provide an overview of the current state of knowledge on normal N response and response to N stress, as well as their interrelationships with other abiotic stresses. Nitrogen is an important macroelement for plant growth. However, plant can't use atmospheric nitrogen as such and depend on its availability in more reactive forms such as urea, nitrate, ammonium, amino acids, etc. Even legumes depend on symbiotic N-fi xing bacteria to convert N 2 into ammonium ions to meet their N requirements. Therefore, the term nitrogen (N) is used in this review to represent a broad range of reactive species of N compounds. In agricultural soils, N compounds and other nutrients have to be constantly replenished as fertilizers/manures to enable repetitive cropping. As N fertilizers are expensive, N-use effi ciency becomes an important determinant of crop productivity. Keywords

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Light Regulation of Nitrate uptake, Assimilation and Metabolism

Cited by 23 publications

References 146 publications

Mutation of the regulatory phosphorylation site of tobacco nitrate reductase results in high nitrite excretion and NO emission from leaf and root tissue

Mutation of the regulatory phosphorylation site of tobacco nitrate reductase results in high nitrite excretion and NO emission from leaf and root tissue

HY5 and HYH are positive regulators of nitrate reductase in seedlings and rosette stage plants

Nitrogen and Stress

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