Nitrogen Metabolism in Citrus Based on Expressed Tag Analysis

Marcondes, Jackson; Lemos, Eliana Gertrudes Macedo

doi:10.1007/978-94-007-4171-3_17

Cited by 5 publications

(9 citation statements)

References 38 publications

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“…NR and NiR has been reported for various organs in citrus, but it is probably mainly expressed in the leaves [ 5 ]. GDH transcripts have been shown to exist in the leaves of tea and peach plants [ 36 , 54 ].…”

Section: Resultsmentioning

confidence: 99%

“…GDH transcripts have been shown to exist in the leaves of tea and peach plants [ 36 , 54 ]. Lastly, a previous study showed that AS was expressed in leaves, but that it was predominantly expressed in fruit tissues [ 5 ]. In the present study, the HgNiR , HgGS , HgGDH , and HgAS genes were expressed in roots ( Fig 3 ), leaves ( Fig 4 ), and fruits ( Fig 5 ) of citrus cultivar ‘Huangguogan’.…”

Section: Resultsmentioning

confidence: 99%

“…Among all the nutrients involved in plant metabolism, N is a major limiting factor for plant production [ 2 ] and an essential structural constituent of proteins, RubisCO, nucleic acids, and chlorophyll, in addition to some hormones [ 3 ]. N fertilizer plays a vital role in citrus tree growth, fruit yield and quality, as shown by several reports on the effects of N application rate on citrus growth [ 4 , 5 ]. Sufficient levels of N support regular plant growth and help plants to defend against stress [ 6 – 8 ].…”

Section: Introductionmentioning

confidence: 99%

“…Nitrate (NO 3 − ) reduction to NH 4 + is mediated by nitrate NR and NiR; NH 4 + is then converted by GS to glutamine and in turn levels of α-ketoglutarate are equilibrated by GDH activity. Finally, glutamate together with oxaloacetate can be used to generate aspartate and asparagine by the sequential action of aspartate aminotransferase and AS [ 5 ].…”

Section: Introductionmentioning

confidence: 99%

“…NiR is regulated transcriptionally, usually in coordination with NR, to avoid nitrite toxicity. For this reason, cells must contain enough NiR to reduce all the nitrite produced by NR [ 5 ]. A previous report showed that NiR was predominant and at similar levels in leaf and fruit tissues in citrus [ 28 ].…”

Section: Introductionmentioning

confidence: 99%

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Effect of nitrogen supply on nitrogen metabolism in the citrus cultivar ‘Huangguogan’

et al. 2019

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Nitrogen metabolism in citrus has received increased attention due to its effects on plant growth and productivity. However, little is known about the effects of nitrogen fertilization on nitrogen metabolism in young trees of citrus cultivar ‘Huangguogan’ (Citrus reticulata × Citrus sinensis). Here, genes encoding nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), glutamate dehydrogenase (GDH), and asparagine synthetase (AS), represented as HgNR, HgNiR, HgGS, HgGDH, and HgAS, respectively, were cloned from Huangguogan. Deduced protein sequences were analyzed and proteins were confirmed to be localized in their respective cellular organelles. Moreover, pot-cultured ‘Huangguogan’ seedlings were fertilized with 0 (N1), 1.36 (N2), 1.81 (N3), 2.26 (N4), or 2.72 (N5) kg N/year, for 12 months. Enzyme activity and enzyme-gene expression were studied in roots, leaves, and fruits at different stages. Finally, the effects of N application rate on root activity, leaf N, soluble protein, yield, and fruit quality at the ripening stage were measured. The results showed that: 1) HgNR, HgNiR, HgGDH, and HgAS gene products were found mainly in the cytoplasm and plasma membrane, while HgGS gene product was found mainly in cytoplasm and mitochondria. 2) Gene expression and enzyme activity differed among plant organs. As the root is in permanent direct contact with the soil we suggest that root gene expression and enzyme activity can be used as reference to determine N application rate. 3) Yield, fruit quality, enzyme activity, and enzyme-related gene expression were considerably lower at low than at high-N supply. However, they were all inhibited by excess nitrogen (i.e., 2.72 kg/year). Therefore, we recommend 1.81 kg N/year as the optimal N application rate for young ‘Huangguogan’ trees.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of nitrogen supply on nitrogen metabolism in the citrus cultivar ‘Huangguogan’

et al. 2019

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Metabolic adjustments in forage oat (Avena sativa L.) genotypes under different sowing windows

Kaur

Goyal

2021

Physiol Mol Biol Plants

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Prokaryotic-Type Aspartate Aminotransferase in Sorghum Leaves: Localization, Distribution and Potential Role

Omari

Mrid

Bouargalne

et al. 2020

Russ J Plant Physiol

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The first part of this work consists in the identification of a prokaryotic-type bifunctional enzyme (aspartate aminotransferase, PT-AAT) in photosynthetic cells of Sorghum-sudangrass hybrid seeds Sorghum × drummondii (Nees ex Steud.) Millsp. and Chase. The results obtained show that the enzyme is constituted by a subunit of 45 kDa immunologically similar to the enzymes of C 3 plants and gymnosperms. This result suggests a high degree of conservation of the PT-AAT in higher plants. To investigate whether the expression of AAT is associated with the differentiation of leaves, we analyzed the chlorophyll levels and AAT, glutamine synthetase (GS), glutamate synthase (GOGAT), isocitrate dehydrogenase (IDH), Rubisco and nitrate reductase (NR) contents in serial sections of the leaves. The chlorophyll content was high in the top sections; and then decreased toward basal sections in a continuous gradient. The Rubisco and NR contents matched the pattern of chlorophyll in the leaves with high levels in the aged section and very low levels in the basal sections. In contrast to chlorophyll, Rubisco and NR contents, GS 2 and Fd-GOGAT polypeptides markedly increased from the top to the basal sections of leaves. However the patterns of AAT and IDH polypeptides did not change in different sections. In the second part of this work, to determine the relative localization of AAT, mesophyll cells (MCs) and bundle-sheath cells (BSCs) of sorghum leaves were separated by cellulase and macerase digestion. PT-AAT protein was most abundant in MC fraction than BSC fraction.

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Nitrogen Metabolism in Citrus Based on Expressed Tag Analysis

Cited by 5 publications

References 38 publications

Effect of nitrogen supply on nitrogen metabolism in the citrus cultivar ‘Huangguogan’

Effect of nitrogen supply on nitrogen metabolism in the citrus cultivar ‘Huangguogan’

Metabolic adjustments in forage oat (Avena sativa L.) genotypes under different sowing windows

Prokaryotic-Type Aspartate Aminotransferase in Sorghum Leaves: Localization, Distribution and Potential Role

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