The elusive cytokinin biosynthetic pathway | Wendy …

This is the first unequivocal demonstration of cytokinin biosynthesis in a normal plant tissue because precursors incorporation into cytokinins was demonstrated by MS.

Unlike in the conventional CK biosynthesis pathway in plants, ..

An alternative cytokinin biosynthesis pathway - Europe …

(B) The cytokinin biosynthesis pathway, ..

Although many studies established nitric oxide (NO) as a signaling molecule in plants, the identification of target molecules of NO has remained elusive due to the lack of in depth molecular studies. Our quantitative proteome analysis suggests the differential regulation of 248 proteins and dynamic regulation of metabolic pathways by exogenous NO donor in chickpea. This is the first report in legumes pointing at the potential candidates that attribute the reported functions of NO in plants.

An alternative cytokinin biosynthesis pathway. - CAB …

The biosynthetic pathways of cytokinins and their related genes in higher plants have been well documented (). The first step of cytokinin biosynthesis in higher plants is isopentenylation of ATP and ADP catalyzed by isopentenyltransferase (IPT) using dimethylallyl diphosphate as a substrate (; ). This is thought to be a rate-limiting step of cytokinin biosynthesis. In , nine genes encoding IPT have been cloned, and transgenic plants overexpressing these genes show elevated concentrations of endogenous cytokinins (). Furthermore, the application of a promoter of floral homeotic genes would be useful for inducing transgenes in a floral organ-specific manner. The floral homeotic genes () and () are specifically expressed in whorls 1 and 2 and whorls 2 and 3, respectively (; ). Therefore, transgenic plants expressing under the control of the promoters of these genes would specifically elevate cytokinin concentration and cytokinin signal in the sepals and petals and in the petals and stamens, respectively.

CSIRO PUBLISHING | Functional Plant Biology

Sponsel, V. M. (1995). "Gibberellin biosynthesis and metabolism". Plant Hormones: Physiology, Biochemistry and Molecular Biology. Dordrecht: Kluwer. pp. 66-97.

Lead toxicity in plants - SciELO

McGaw, B. A. (1995). "Cytokinin biosynthesis and metabolism". Plant Hormones: Physiology, Biochemistry and Molecular Biology. Dordrecht: Kluwer. pp.98-117.

An alternative cytokinin biosynthesis pathway ..

Cytokinin reportedly plays an important role in the regulation of flower morphology. In , the number of floral organs, such as petals, stamens, and pistils, is increased after 6-benzylaminopurine treatment of flower buds (; ). Such an increase in the number of floral organs is promoted by cytokinin-mediated induction of gene expression involved in meristematic activity and organ differentiation (; ). In , treatment with forchlorfenuron (CPPU), which inhibits cytokinin degradation through cytokinin oxidase/dehydrogenase (CKX) inhibition (), induces corolla expansion following an increase in the cell number (; ). Furthermore, some genes involved in cytokinin biosynthesis and early signaling pathways are regulated by the gene, which is responsible for the large-flowered phenotype in petunia (; , ).

the metabolic pathway and the regulation in higher plants.

To analyze the relationship between flower morphology and organ-specific promotion of cytokinin biosynthesis within flower buds, we introduced () into torenia ( L.) under the control of () or () promoter. plants had an increased number of petals, whereas plants had an expanded corolla, a paracorolla, and serrated petal margins along with an increased number of petals. In plants, marked receptacle enlargement was observed when the flower buds were in the early corolla development stage in which the paracorolla primordia differentiate. As expected, was expressed in the sepals and petals of plants, and in the petals and stamens of plants. Furthermore, the type-A response regulator () and cytokinin oxidase () genes, which were used as indices of cytokinin signal, showed the same expression patterns as the transgene. These findings indicate that expansion of the corolla and development of the paracorolla and serrated petal margins after receptacle enlargement in plants are induced by localized elevated cytokinin signal in the petals and stamens. In contrast, localized elevated cytokinin signal in the sepals and petals only induced an increase in the number of petals. Therefore, an elevated cytokinin signal in the stamen may be important for inducing corolla expansion and for developing a paracorolla and serrated petal margins.

Interactions between plant hormones and heavy metals …

In the AMP pathway zeatin is synthesized from an isopentenyl donor, dimethylallyl diphosphate (DMAPP), and AMP, ADP, or ATP by isopentenyltransferases.