Temporal Study of the Effect of Phosphinothricin on the Activity of Glutamine Synthetase, Glutamate Dehydrogenase and Nitrate Reductase in Medicago sativa L.

doi:10.1016/S0176-1617(11)80028-3

Journal of Plant Physiology

Volume 136, Issue 4, July 1990, Pages 410-414

https://doi.org/10.1016/S0176-1617(11)80028-3 Get rights and content

Summary

In a preliminary work we showed that when plants were sprayed with several doses of glufosinate, GS activity of the leaf was reduced by 50% after 48 h of application of 250 µM herbicide. Enzyme inhibition was accompained by a dramatic accumulation of ammonia. In this paper we analyze the time-course effect of phosphinothricin on nitrogen metabolism. Our results show that GS activity is the first process affected; more than 50% activity reduction is observed after 2 h of a 1,000 µM treatment, whereby ammonia values 400% higher than control were reached. NRase did not change until 24 h of assay, whereas protein content was reduced after 48 h. GDH activity was enhanced, but only 24 h after starting the treatment. These results indicate that the main target of PPT action is on GS activity, and other processes are long-term modified. GDH could, perhaps, reassimilate some of the ammonia produced but its activity is not able to completely prevent, the injury caused by phosphinothricin.

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Cited by (39)

A low red/far-red ratio restricts nitrogen assimilation by inhibiting nitrate reductase associated with downregulated TaNR1.2 and upregulated TaPIL5 in wheat (Triticum aestivum L.)
2024, Plant Physiology and Biochemistry
Understanding the physiological mechanism underlying nitrogen levels response to a low red/far-red ratio (R/FR) can provide new insights for optimizing wheat yield potential but has been not well documented. This study focused on the changes in nitrogen levels, nitrogen assimilation and nitrate uptake in wheat plants grown with and without additional far-red light. A low R/FR reduced wheat nitrogen accumulation and grain yield compared with the control. The levels of total nitrogen, free amino acid and ammonium were decreased in leaves but nitrate content was temporarily increased under a low R/FR. The nitrate reductase (NR) activity in leaves was more sensitive to a low R/FR than glutamine synthetase, glutamate synthase, glutamic oxalacetic transaminase and glutamic-pyruvic transaminase. Further analysis showed that a low R/FR had little effect on the NR activation state but reduced the level of NR protein and the expression of encoding gene TaNR1.2. Interestingly, a low R/FR rapidly induced TaPIL5 expression rather than TaHY5 and other members of TaPILs in wheat, suggesting that TaPIL5 was the key transcription factor response to a low R/FR in wheat and might be involved in the downregulation of TaNR1.2 expression. Besides, a low R/FR downregulated the expression of TaNR1.2 in leaves earlier than that of TaNRT1.1/1.2/1.5/1.8 in roots, which highlights the importance of NR and nitrogen assimilation in response to a low R/FR. Our results provide revelatory evidence that restricted nitrate reductase associated with downregulated TaNR1.2 and upregulated TaPIL5 mediate the suppression of nitrogen assimilation under a low R/FR in wheat.
Postponed and reduced basal nitrogen application improves nitrogen use efficiency and plant growth of winter wheat
2018, Journal of Integrative Agriculture
Excessive nitrogen (N) fertilization with a high basal N ratio in wheat can result in lower N use efficiency (NUE) and has led to environmental problems in the Yangtze River Basin, China. However, wheat requires less N fertilizer at seedling growth stage, and its basal N fertilizer utilization efficiency is relatively low; therefore, reducing the N application rate at the seedling stage and postponing the N fertilization period may be effective for reducing N application and increasing wheat yield and NUE. A 4-year field experiment was conducted with two cultivars under four N rates (240 kg N ha⁻¹ (N240), 180 kg N ha⁻¹ (N180), 150 kg N ha⁻¹ (N150), and 0 kg N ha⁻¹ (N0)) and three basal N application stages (seeding (L0), four-leaf stage (L4), and six-leaf stage (L6)) to investigate the effects of reducing the basal N application rate and postponing the basal N fertilization period on grain yield, NUE, and N balance in a soil-wheat system. There was no significant difference in grain yield between the N180L4 and N240L0 (control) treatments, and the maximum N recovery efficiency and N agronomy efficiency were observed in the N180L4 treatment. Grain yield and NUE were the highest in the L4 treatment. The leaf area index, flag leaf photosynthesis rate, flag leaf nitrate reductase and glutamine synthase activities, dry matter accumulation, and N uptake post-jointing under N180L4 did not differ significantly from those under N240L0. Reduced N application decreased the inorganic N content in the 0–60-cm soil layer, and the inorganic N content of the L6 treatment was higher than those of the L0 and L4 treatments at the same N level. Surplus N was low under the reduced N rates and delayed basal N application treatments. Therefore, postponing and reducing basal N fertilization could maintain a high yield and improve NUE by improving the photosynthetic production capacity, promoting N uptake and assimilation, and reducing surplus N in soil-wheat systems.
Origanum vulgare essential oils inhibit glutamate and aspartate metabolism altering the photorespiratory pathway in Arabidopsis thaliana seedlings
2018, Journal of Plant Physiology
Essential oils (EOs) have been extensively studied as valuable eco-friendly compounds with herbicidal activity for weed management. Phytotoxic potential of EOs, extracted from a wild population of Origanum vulgare ssp. hirtum (Link) Ietswaart, has been here evaluated on plant model Arabidopsis, through a physiological and metabolomic approach. The EOs composition was mainly characterized by monoterpenes and sesquiterpenes, with a strong abundance of two monoterpenic phenols, namely carvacrol and thymol, and the monoterpene o-cymene. The in vitro bioassay confirmed a strong phytotoxic effect of EOs on Arabidopsis rosettes, showing by both a strong growth reduction and highly chlorotic leaves. In well-developed seedlings, EOs firstly caused growth reduction and leaf chlorosis, together with a series of interconnected metabolic alterations: i) impairing the nitrogen assimilation into amino acids, which affects in particular the glutamine metabolism; and as consequence ii) excessive accumulation of toxic ammonia into the leaves, associated with oxidative stress and damage; iii) declining the efficiency of the photosynthetic apparatus, connected to the reduced CO₂ fixation and photooxidation protection; iv) impairing the photorespiratory pathway. Overall, the results highlights that EOs alters principally the ability of Arabidopsis seedlings to incorporate inorganic nitrogen into amino acids, principally glutamine, leading to a dramatic accumulation of ammonia in leaf cells. This primary effect induces, in turn, a cascade of reactions that limits the efficiency of PSII, inducing oxidative stress and finally causing a strong plant growth reduction, leaf necrosis and eventually plant death.
These findings suggest that O. vulgare EOs might be proficiently exploited as a potential bioherbicide in an ecofriendly agriculture. Moreover, its multitarget activity could be advantageous in limiting weed resistance phenomenon.
Winter and spring night-warming improve root extension and soil nitrogen supply to increase nitrogen uptake and utilization of winter wheat (Triticum aestivum L.)
2018, European Journal of Agronomy
Citation Excerpt :
The activation state of NR was determined as a percentage ratio between NR activity measured in the presence of MgCl2 (NRact) and NR measured with EDTA (NRmax). Glutamine synthetase (GS) activity was determined as described by (Lacuesta et al., 1990) with minor modifications. Briefly, the reaction medium (final volume 105 uL) consisted of 100 mM HEPES-KOH (pH 7.8), 150 mM glutamate, 10 mM MgCl2, 15 mM ATP, 10 mM NaOH, 10 mM hydroxylamine, and 2 mM EDTA.
Elucidating the effects of asymmetric warming during winter and spring will help develop a feasible crop management strategy for climate change. Field experiments were conducted using the Yangmai-13 (vernal type) and Yannong-19 (semi-winter type) winter wheat cultivars to investigate the effects of night-warming during winter (warming by 1.47–1.53 °C from tillering to jointing), spring (warming by 1.68–1.77 °C from jointing to booting), and winter + spring (warming by 1.53–1.60 °C from tillering to booting) on plant growth and N utilization in 2014–2016. The results showed that the grain yield, N agronomic efficiency (NAE), and N recovery efficiency (NRE) of both cultivars were highly increased in response to night-warming, which were associated with enhanced dry matter and N accumulation, and winter + spring night-warming resulted in greater increases than winter night-warming and spring night-warming. Furthermore, the increase in pre-anthesis N accumulation was much higher than after anthesis, resulting in a greater increase in post-anthesis dry matter accumulation due to more leaf N distribution at anthesis to support photosynthetic production. Root growth characteristics (i.e., root length, surface area and volume, and root bleeding intensity) were significantly promoted, which favored plant N uptake. Soil urease and protease activity as well as the net N mineralization rate, which are involved in soil N supply capacity, were increased, whereas soil inorganic N content and apparent N surplus were clearly decreased, which indicated that plant N uptake capacity was highly improved in response to night-warming conditions. In conclusion, winter and spring night-warming improve pre-anthesis root growth and N uptake ability to promote plant growth, resulting in increased N utilization efficiency with reduced N fertilizer loss, and winter + spring night-warming has more advantages for N uptake and utilization of winter wheat.
The imbalance between C and N metabolism during high nitrate supply inhibits photosynthesis and overall growth in maize (Zea mays L.)
2017, Plant Physiology and Biochemistry
Citation Excerpt :
At least three biological replicates for each measurement point were made. Nitrate reductase (NR, EC 1.7.1.1) was extracted according to the method described by Lacuesta et al. (1990), with some modifications. A sample of 0.1 g FW was extracted in a mortar cooled with liquid nitrogen using 1 mL of extraction buffer containing 200 mM Tris-HCl (pH = 8.5), 25 mM KH2PO4, 25 mM K2HPO4, 5 mM Na2-EDTA, 1 mM cysteine, 10 mM FAD (freshly prepared), 0.5% (w/v) BSA and 2.5% (w/v) PVPP.
Nitrogen (N) is an important regulator of photosynthetic carbon (C) flow in plants, and an adequate balance between N and C metabolism is needed for correct plant development. However, an excessive N supply can alter this balance and cause changes in specific organic compounds associated with primary and secondary metabolism, including plant growth regulators. In previous work, we observed that high nitrate supply (15 mM) to maize plants led to a decrease in leaf expansion and overall biomass production, when compared with low nitrate supply (5 mM). Thus, the aim of this work is to study how overdoses of nitrate can affect photosynthesis and plant development. The results show that high nitrate doses greatly increased amino acid production, which led to a decrease in the concentration of 2-oxoglutarate, the main source of C skeletons for N assimilation. The concentration of 1-aminocyclopropane-1-carboxylic acid (and possibly its product, ethylene) also rose in high nitrate plants, leading to a decrease in leaf expansion, reducing the demand for photoassimilates by the growing tissues and causing the accumulation of sugars in source leaves. This accumulation of sugars, together with the decrease in 2-oxoglutarate levels and the reduction in chlorophyll concentration, decreased plant photosynthetic rates. This work provides new insights into how high nitrate concentration alters the balance between C and N metabolism, reducing photosynthetic rates and disrupting whole plant development. These findings are particularly relevant since negative effects of nitrate in contexts other than root growth have rarely been studied.
Genetic improvement of nitrogen uptake and utilization of winter wheat in the Yangtze River Basin of China
2016, Field Crops Research
Citation Excerpt :
Increased N distribution to leaves to improve net photosynthetic rate (Pn), and/or high Pn might enhance plants N uptake ability. Nitrate absorbed by wheat is reduced to nitrite in the cytosol by the enzyme NR, and ammonium is then converted into glutamine and glutamate in the plastid/chloroplast by the GS enzyme system (Lacuesta et al., 1990; Singh et al., 2014). NR is considered to be the bottleneck in nitrate assimilation (Singh et al., 2014); GS lies at the intersection of the C and N metabolic pathways, and its manipulation in wheat plants could potentially increase NUE through more efficient internal recycling of N from older to new leaves (Singh et al., 2014; Thomsen et al., 2014).
Verifying the ongoing genetic improvement of nitrogen use efficiency (NUE) and determining the physiological basis of the improvement will aid breeders and agronomists in developing new wheat (Triticum aestivum L.) cultivars, with the aim of high yields and low N fertilizer requirements. A two-year field experiment was conducted with 32 wheat cultivars, which were bred or widely planted in the Yangtze River Basin from 1950 to 2005 under two N application rates (0 and 225 kg N ha⁻¹) in Nanjing, China, to examine the improvement of N uptake and utilization, as well as its physiological basis. Grain yield, harvest index (HI), N recovery efficiency (NRE), and N agronomic efficiency (NAE) increased with cultivar development from the 1950s to the 2000s. N accumulation at maturity of modern cultivars was higher than for the older cultivars, which mainly resulted in increased N accumulation amount and N accumulation rate during the jointing to anthesis (J–A) growth period. With cultivar development, the activities of nitrate reductase (NR) and glutamine synthetase (GS) in leaves increased at the booting and anthesis stages, while remained stable during the grain filling stage, indicating that N assimilation increased prior to anthesis, resulting in an increase in pre-anthesis N concentration and uptake in plants. Leaf N concentration (LNC) increased at anthesis, and the increase was larger than that observed in other organs. At maturity, LNC and grain N concentration (GNC) decreased, while the amount of N in stems, chaff, and the total plants increased, indicating that increased N in leaves at anthesis enhances N remobilization to grain. The N distribution amount to leaves at anthesis increased with cultivar development, but decreased at maturity. Post-anthesis N translocation amount and N translocation efficiency of vegetative organs increased, and the N translocation efficiencies of leaves were higher than those of other organs. NRE and NAE were positively correlated with grain yield, kernel number, kernel weight, HI, N uptake during the J–A growth period, and post-anthesis N translocation. Grain yield and HI were positively correlated with pre-anthesis N uptake, and N translocation of each organ, while there was no relationship with biomass or post-anthesis N uptake. Therefore, increased pre-anthesis N assimilation ability and post-anthesis N translocation were strongly associated with grain yield, and N uptake and utilization efficiency.

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Journal of Plant Physiology

Summary

References (27)

Assay of proteins in the presence of interfering materials

Anal. Biochem.

Effect of Phosphinothricin (Glufosinate) on Activities of Glutamine Synthetase and Glutamate Dehydrogenase in Medicago sativa L.

J. Plant Physiol.

Inhibition of pea leaf glutamine synthetase by methionine sulfoximine, phosphinothricin and other glutamate analogues

Phytochem.

Studies on the mechanism of inhibition by phosphinothricin of glutamine synthetase isolated from Triticum aestivum L.

J. Plant Physiol.

Regulation of nitrate reductase activity in higher plants

Phytochemistry

Role and regulation of L-glutamate dehydrogenase activity in higher plants

Phytochem.

Evidence for the assimilation of ammonia via the glutamine pathway in nitrate grown Lemna minor

FEBS Lett.

Crop production in artificial solutions and in soils with special reference to factors influencing yields and absorption of inorganic nutrients

Soil Sci.

A study of the role of glutamate dehydrogenase in the nitrogen metabolism of Arabidopsys thaliana

Planta

Sources of ammonium in oat leaves treated with tabtoxin or methionine sulfoximine

Plant Physiol.

Root nodule enzymes of ammonia assimilation in alfalfa (Medicago sativa L.)

Plant Physiol.

Ammonia, glutamine, and asparagine: a carbon-nitrogen interface

Can. J. Bot.

Influence of the light factor on physiological effects of the herbicide Hoe 39866

Aspects of Applied Biol.

Cited by (39)

A low red/far-red ratio restricts nitrogen assimilation by inhibiting nitrate reductase associated with downregulated TaNR1.2 and upregulated TaPIL5 in wheat (Triticum aestivum L.)

Postponed and reduced basal nitrogen application improves nitrogen use efficiency and plant growth of winter wheat

Origanum vulgare essential oils inhibit glutamate and aspartate metabolism altering the photorespiratory pathway in Arabidopsis thaliana seedlings

Winter and spring night-warming improve root extension and soil nitrogen supply to increase nitrogen uptake and utilization of winter wheat (Triticum aestivum L.)

The imbalance between C and N metabolism during high nitrate supply inhibits photosynthesis and overall growth in maize (Zea mays L.)

Genetic improvement of nitrogen uptake and utilization of winter wheat in the Yangtze River Basin of China