\Cytokinin oxidase/dehydrogenase (CKX) activity in wild and ethylene-insensitive mutant eti5 type of Arabidopsis thaliana (L.) Heynh plants and the effect of cytokinin N1-(2-chloro-4-pyridyl)-N2-phenylurea on enzymatic activity and leaf morphology

The overexpression of the algal glutamine synthetase (GS) gene DvGS1 in Arabidopsis thaliana resulted in higher plant biomass and better growth phenotype. The purpose of this study was to recognize the biological mechanism for the growth improvement of DvGS1-transgenic Arabidopsis. A series of molecular and biochemical investigations related to nitrogen and carbon metabolism in the DvGS1-transgenic line was conducted. Analysis of nitrogen use efficiency (NUE)-related gene transcription and enzymatic activity revealed that the transcriptional level and enzymatic activity of the genes encoding GS, glutamate synthase, glutamate dehydrogenase, alanine aminotransferase and aspartate aminotransferase, were significantly upregulated, especially from leaf tissues of the DvGS1-transgenic line under two nitrate conditions. The DvGS1-transgenic line showed increased total nitrogen content and decreased carbon: nitrogen ratio compared to wild-type plants. Significant reduced concentrations of free nitrate, ammonium, sucrose, glucose and starch, together with higher concentrations of total amino acids, individual amino acids (glutamate, aspartate, asparagine, methionine), soluble proteins and fructose in leaf tissues confirmed that the DvGS1-transgenic line demonstrated a higher efficiency of nitrogen assimilation, which subsequently affected carbon metabolism. These improved metabolisms of nitrogen and carbon conferred the DvGS1-transgenic Arabidopsis higher NUE, more biomass and better growth phenotype compared with the wild-type plants.

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New Generation of Arabidopsis thaliana Cytokinin Oxidase/Dehydrogenase Inhibitors Affect Shoot/Root Growth and Seed Yield

Meta-topolin: A Growth Regulator for Plant Biotechnology and Agriculture ◽

10.1007/978-981-15-9046-7_21 ◽

2021 ◽

pp. 293-316

Author(s):

Jana Bíbová ◽

Marek Zatloukal ◽

Radoslav Koprna ◽

Lukáš Spíchal ◽

Miroslav Strnad

Keyword(s):

Arabidopsis Thaliana ◽

Root Growth ◽

Seed Yield ◽

Cytokinin Oxidase ◽

New Generation

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Expression of lavender AGAMOUS-like and SEPALLATA3-like genes promote early flowering and alter leaf morphology in Arabidopsis thaliana

Planta ◽

10.1007/s00425-021-03703-3 ◽

2021 ◽

Vol 254 (3) ◽

Author(s):

Ayelign M. Adal ◽

Elinor Binson ◽

Lisa Remedios ◽

Soheil S. Mahmoud

Keyword(s):

Arabidopsis Thaliana ◽

Leaf Morphology ◽

Early Flowering

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Mild temperature stress modulates cytokinin content and cytokinin oxidase/dehydrogenase activity in young pea plants

Acta Agronomica Hungarica ◽

10.1556/aagr.57.2009.1.4 ◽

2009 ◽

Vol 57 (1) ◽

pp. 33-40 ◽

Cited By ~ 5

Author(s):

I. Vaseva ◽

D. Todorova ◽

J. Malbeck ◽

A. Travničkova ◽

I. Machačkova

Keyword(s):

Low Temperature ◽

Enzymatic Activity ◽

Dehydrogenase Activity ◽

Growth Conditions ◽

Zeatin Riboside ◽

Cytokinin Oxidase ◽

Temperature Stresses ◽

Isopentenyl Adenine ◽

Mild Temperature ◽

Adaptive Reactions

Cytokinin oxidase/dehydrogenase (CKX: EC 1.5.99.12) is able to provide a means for the rapid turnover of its substrate and it has been considered responsible for changes in the cytokinin pool in an adverse environment. Mild temperature stresses (10°C and 33°C average) were applied to young pea plants of two varieties (cvs. Manuela and Scinado) in order to assess the response of the cytokinin pool and CKX activity to altered growth conditions. Both temperature treatments increased the isopentenyl adenine (iP) and isopentenyl adenine riboside (iPR) contents in stressed plants. This trend was far more pronounced in the leaves. Low temperature additionally resulted in elevated cis zeatin riboside ( cis ZR) and CKX activity. Heat did not influence the enzymatic activity in the leaves, while opposing trends were observed in the root-derived CKX activity of the two tested varieties. The data suggest that variance in the temperature provokes adaptive reactions in the cytokinin pool, which is maintained by CKX activity.

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The role of phytochrome C in gravitropism and phototropism in Arabidopsis thaliana

Functional Plant Biology ◽

10.1071/fp08013 ◽

2008 ◽

Vol 35 (4) ◽

pp. 298 ◽

Cited By ~ 11

Author(s):

Prem Kumar ◽

Crystal E. Montgomery ◽

John Z. Kiss

Keyword(s):

Arabidopsis Thaliana ◽

Blue Light ◽

Leaf Morphology ◽

Red Light ◽

Phytochrome A ◽

Inflorescence Stems ◽

Root Gravitropism ◽

Positive Effect ◽

Rosette Leaf

The phytochrome (phy) photoreceptors, which consist of a small gene family PHYA-E in dicot plants, play important roles in regulating many light-induced responses in plants. Although the best characterised phytochromes are phytochrome A (phyA) and phytochrome (phyB), the functions of phyD and phyE have been increasingly studied. Phytochrome C (phy C) has been the most poorly understood member of the photoreceptor family, since isolation of phyC mutants only has been accomplished within the last few years. Recent reports show that phyC functions in hypocotyl elongation, rosette leaf morphology, and timing of flowering. In the present study, we show that phyC plays a role in tropisms in seedlings and inflorescence stems of light-grown Arabidopsis thaliana (L.) Heynh. (Wassilewskija ecotype). Phytochrome C has a positive effect on gravitropism in hypocotyls and stems, but it has a limited role in root gravitropism. In contrast, phyC attenuates the positive phototropic response to blue light in hypocotyls and the red-light-based positive phototropism in roots. Phytochrome D (phy D) also mediates gravitropism in hypocotyls and inflorescence stems and attenuates positive phototropism in response to blue in hypocotyls and stems. Thus, phyC can be added to the list of the other four phytochromes, which play various roles in both gravitropism and phototropism in plant organs. This report also supports the growing body of evidence demonstrating cross talk between phytochromes and blue-light photoreceptors.

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