Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.7.1.1 (nitrate reductase)
3,728 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pokkah boeng disease (PBD) is a foliar disease causing severe losses in sugarcane crop production. Research into resistance mechanisms against the causal agent, Fusarium verticillioides, is particularly important for farmers and researchers. This work based on the comprehensive analysis of metabolic, proteomic, and bioinformatics data on nitrogen (N) metabolism, which revealed that this biosynthetic reactions was closely related to resistance mechanisms in the sugarcane- F. verticillioides interaction. Our results suggested that pathogen infection reduced the suppression of nitrate reductase (NR) activity, reducing ammonium nitrogen (NH₄⁺-N) and nitrate nitrogen (NO₃^--N) assimilation, which reduces glutamine synthetase (GS), glutamate synthetase (GOGAT) activity and polynucleotide synthesis and promotes RNA degradation, resulting in a decrease in ribosome levels and protein synthesis. Cysteine was found to be associated with the symptoms of PBD, while alanine, lysine, proline, and glutamic acid were found to be involved in protective and regulatory mechanisms as well. Additionally, glutamate played an important role in sugarcane defense against pathogens through the biosynthesis of proline and polyamines. Cyanamide, glutamate, proline, tyrosine, and arachidonic acid metabolism actively participate in resistance and response to stress. C5XPZ6 and C5XCA6 were considered to be critical proteins and key effectors according to this study. In conclusion, we have identified potential proteins and pathways involved in sugarcane resistance to F. verticillioides, revealing new findings that may be useful in the design of future diagnostics or sugarcane protection strategies and providing new insights into the molecular mechanisms of sugarcane-pathogen interactions.
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PMID:Metabolic and proteomic analysis of nitrogen metabolism mechanisms involved in the sugarcane - Fusarium verticillioides interaction. 3259 20

This paper originates from a presentation at the IIIrd International Congress on Crassulacean Acid Metabolism, Cape Tribulation, Queensland, Australia, August 2001. The C3-crassulacean acid metabolism tropical hemiepiphytic tree, Clusia minor L., is highly flexible in terms of ecological sites occupied, life forms, and photosynthetic and metabolic pathways. We studied nitrogen uptake patterns in two glasshouse ¹⁵N-labelling experiments using hydroponically-grown plants and excised roots of pot-grown C. minor, and investigated leaf and root nitrate reductase activity (NRA) in a field study in Venezuela. The results of both ¹⁵N-uptake experiments indicate that C. minor utilized all offered nitrogen sources, but clearly preferred to take up NH4⁺ over glycine (GLY) and NO3^-. The uptake pattern of NH4⁺ and NO3^- was identical in intact plants and excised roots, and NH4⁺ was taken up to a much larger extent in both experiments. Gas chromatography-mass spectrometry (GC-MS) analysis of amino acids in excised roots revealed that glutamine (45 atom-%), glutamate (23 atom-%) and alanine (34 atom-%) accounted for most of the labelled soluble amino acids after 2-h labelling with ¹⁵NH4⁺. High amounts of ¹⁵N in GLY and serine confirmed that GLY was taken up as an intact molecule and metabolized in the excised roots. With ¹⁵NO3^- labelling, only a small amount of ¹⁵N was found in the amino acid fraction, indicating a low NO3^- assimilation rate by nitrate reductase. This was confirmed by low NRA of leaves and roots in C. minor plants in Venezuela. It appears, therefore, that a high degree of plasticity is not reflected in nitrogen uptake and metabolism. Although C. minor exhibits clear preferences for NH4⁺ uptake, it can utilize other sources of nitrogen, and the nitrogen uptake pattern represents an adaptation to the natural environments in which C. minor can grow.
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PMID:Flexibility of nitrogen metabolism in the tropical C3crassulacean acid metabolism tree species Clusia minor. 3268 21

Floral nectar is a sugary solution produced by nectaries to attract and reward pollinators. Nectar metabolites, such as sugars, are synthesized within the nectary during secretion from both pre-stored and direct phloem-derived precursors. In addition to sugars, nectars contain nitrogenous compounds such as amino acids; however, little is known about the role(s) of nitrogen (N) compounds in nectary function. In this study, we investigated N metabolism in Cucurbita pepo (squash) floral nectaries in order to understand how various N-containing compounds are produced and determine the role of N metabolism in nectar secretion. The expression and activity of key enzymes involved in primary N assimilation, including nitrate reductase (NR) and alanine aminotransferase (AlaAT), were induced during secretion in C. pepo nectaries. Alanine (Ala) accumulated to about 35% of total amino acids in nectaries and nectar during peak secretion; however, alteration of vascular nitrate supply had no impact on Ala accumulation during secretion, suggesting that nectar(y) amino acids are produced by precursors other than nitrate. In addition, nitric oxide (NO) is produced from nitrate and nitrite, at least partially by NR, in nectaries and nectar. Hypoxia-related processes are induced in nectaries during secretion, including lactic acid and ethanolic fermentation. Finally, treatments that alter nitrate supply affect levels of hypoxic metabolites, nectar volume and nectar sugar composition. The induction of N metabolism in C. pepo nectaries thus plays an important role in the synthesis and secretion of nectar sugar.
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PMID:The role of alanine synthesis and nitrate-induced nitric oxide production during hypoxia stress in Cucurbita pepo nectaries. 3311 49


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