Regulation of proline accumulation in detached rice leaves exposed to excess copper

Chen, Chien Teh; Chen, Li-Men; Lin, Chuan Chi; Kao, Ching Huei

doi:10.1016/s0168-9452(00)00393-9

Cited by 170 publications

(98 citation statements)

References 41 publications

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“…are activated. In supra-optimal copper concentration, coffee seedlings showed a significant increase in proline content (Fig 2C and 2D), which is in agreement with Silene vulgaris (Schat et al, 1997), Oriza sativa (Chen et al, 2001) and Zea mays (Wen et al, 2013). However, an interesting fact in the present study was the increase of proline levels in seedlings under copper deficiency in both leaf and root ( Fig.…”

Section: Discussionsupporting

confidence: 88%

Copper (Cu) stress affects carbon and antioxidant metabolism in Coffea arabica seedlings

Santos¹,

Fária²,

Silva³

et al. 2017

Aust J Crop Sci

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Although copper is a micronutrient essential for the normal development of plants, both insufficient and supra optimal doses can disrupt the functioning of metabolism and the production of biomass. To study the biochemical and physiological impacts of deficiency and excess of copper in coffee, we treated 6-month-old seedlings of Coffea arabica L. Catuaí cultivar to three copper treatments: control (0.03 ppm), excess (0.12 ppm) and deficiency (0 ppm) for 60 days. The changes in levels of photosynthetic pigments, biomass allocation, carbohydrate partitioning, antioxidant system and proline levels were evaluated. Under deficiency and excess of copper coffee seedlings showed lower levels of chlorophyll, reduction on dry weight of shoot, lower sugar levels and higher content of hydrogen peroxide. We also observed increased levels of proline and enzymatic activity of the antioxidant system, providing conditions for the reduction of oxidative stress triggered by nutritional imbalance. In general, the results showed that coffee plants invest in antioxidant defense system as an alternative to maintain redox balance when exposed to deficiency or excess copper. However, it is not effective to prevent an increase in lipid peroxidation. Authors may indicate an optimum range for application of copper in coffee.

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Section: Discussionsupporting

confidence: 88%

Copper (Cu) stress affects carbon and antioxidant metabolism in Coffea arabica seedlings

Santos¹,

Fária²,

Silva³

et al. 2017

Aust J Crop Sci

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“…Proline is a multifaceted amino acid with important roles in carbon and nitrogen metabolism; protein synthesis; and protection against various environmental factors such as drought (44), metal toxicity (45,46), osmotic stress (24,25), ultraviolent irradiation (47), unfolded protein stress (26,48), and oxidative stress (19,23,27,28,49). In this study, we explored the role of proline metabolism in oxidative stress protection by characterizing the oxidative stress response of wild-type and putA mutant E. coli strains.…”

Section: Discussionmentioning

confidence: 99%

Proline Metabolism IncreaseskatGExpression and Oxidative Stress Resistance in Escherichia coli

2014

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The oxidation of L-proline to glutamate in Gram-negative bacteria is catalyzed by the proline utilization A (PutA) flavoenzyme, which contains proline dehydrogenase (PRODH) and ⌬ 1 -pyrroline-5-carboxylate (P5C) dehydrogenase domains in a single polypeptide. Previous studies have suggested that aside from providing energy, proline metabolism influences oxidative stress resistance in different organisms. To explore this potential role and the mechanism, we characterized the oxidative stress resistance of wild-type and putA mutant strains of Escherichia coli. Initial stress assays revealed that the putA mutant strain was significantly more sensitive to oxidative stress than the parental wild-type strain. Expression of PutA in the putA mutant strain restored oxidative stress resistance, confirming that depletion of PutA was responsible for the oxidative stress phenotype. Treatment of wild-type cells with proline significantly increased hydroperoxidase I (encoded by katG) expression and activity. Furthermore, the ⌬katG strain failed to respond to proline, indicating a critical role for hydroperoxidase I in the mechanism of proline protection. The global regulator OxyR activates the expression of katG along with several other genes involved in oxidative stress defense. In addition to katG, proline increased the expression of grxA (glutaredoxin 1) and trxC (thioredoxin 2) of the OxyR regulon, implicating OxyR in proline protection. Proline oxidative metabolism was shown to generate hydrogen peroxide, indicating that proline increases oxidative stress tolerance in E. coli via a preadaptive effect involving endogenous hydrogen peroxide production and enhanced catalase-peroxidase activity.T he conversion of L-proline to glutamate is a four-electron oxidation process that is coordinated in two successive steps by the enzymes proline dehydrogenase (PRODH) and ⌬ 1 -pyrroline-5-carboxylate dehydrogenase (P5CDH) (Fig. 1) (1). In eukaryotes, PRODH and P5CDH are separately encoded enzymes localized in the mitochondrion. In Gram-negative bacteria, PRODH and P5CDH are combined into a bifunctional enzyme known as proline utilization A (PutA) (1, 2). The PRODH domain contains a noncovalently bound flavin adenine dinucleotide (FAD) cofactor and couples the two-electron oxidation of proline to the reduction of ubiquinone in the cytoplasmic membrane (3). The product of the PRODH reaction, ⌬ 1 -pyrroline-5-carboxylate (P5C), is subsequently hydrolyzed to glutamate-␥-semialdehyde (GSA), which is then oxidized to glutamate by the NAD ϩ -dependent P5CDH domain (2). In certain Gram-negative bacteria such as Escherichia coli, PutA also has an N-terminal ribbon-helix-helix (RHH) DNA-binding domain (residues 1 to 47) (4). The RHH domain enables PutA to act as an autogenous transcriptional regulator of the putA and putP (highaffinity Na ϩ -proline transporter) genes (4). PutA represses put gene expression by binding to five operator sites in the put regulatory region (5). Transcription of the put genes is activated by proline, which causes a r...

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“…In plants, intracellular proline levels have been found to increase by > 100-fold during stress (42,131). Proline accumulation in plants occurs during exposure to various stresses, including salt (150), drought (9,19), UV radiation (108), heavy metal ions (18), pathogens (33), and oxidative stress (146). Proline accumulation and stress tolerance have been studied in plants by exogenously and endogenously manipulating proline levels (45).…”

Section: Proline Metabolic Adaptation In Plants During Stressmentioning

confidence: 99%

Proline Mechanisms of Stress Survival

Liang

Zhang

Natarajan

et al. 2013

Antioxidants & Redox Signaling

889

576

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Significance: The imino acid proline is utilized by different organisms to offset cellular imbalances caused by environmental stress. The wide use in nature of proline as a stress adaptor molecule indicates that proline has a fundamental biological role in stress response. Understanding the mechanisms by which proline enhances abiotic/biotic stress response will facilitate agricultural crop research and improve human health. Recent Advances: It is now recognized that proline metabolism propels cellular signaling processes that promote cellular apoptosis or survival. Studies have shown that proline metabolism influences signaling pathways by increasing reactive oxygen species (ROS) formation in the mitochondria via the electron transport chain. Enhanced ROS production due to proline metabolism has been implicated in the hypersensitive response in plants, lifespan extension in worms, and apoptosis, tumor suppression, and cell survival in animals. Critical Issues: The ability of proline to influence disparate cellular outcomes may be governed by ROS levels generated in the mitochondria. Defining the threshold at which proline metabolic enzyme expression switches from inducing survival pathways to cellular apoptosis would provide molecular insights into cellular redox regulation by proline. Are ROS the only mediators of proline metabolic signaling or are other factors involved? Future Directions: New evidence suggests that proline biosynthesis enzymes interact with redox proteins such as thioredoxin. An important future pursuit will be to identify other interacting partners of proline metabolic enzymes to uncover novel regulatory and signaling networks of cellular stress response. Antioxid. Redox Signal. 19, 998-1011.

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Regulation of proline accumulation in detached rice leaves exposed to excess copper

Cited by 170 publications

References 41 publications

Copper (Cu) stress affects carbon and antioxidant metabolism in Coffea arabica seedlings

Copper (Cu) stress affects carbon and antioxidant metabolism in Coffea arabica seedlings

Proline Metabolism IncreaseskatGExpression and Oxidative Stress Resistance in Escherichia coli

Proline Mechanisms of Stress Survival

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