Topic
Zeatin
About: Zeatin is a research topic. Over the lifetime, 2467 publications have been published within this topic receiving 64092 citations. The topic is also known as: Zeatin & (E/Z)-zeatin.
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TL;DR: A possibility of the existence of systems of cytokinin signal perception in the evolutionary precursor of chloroplasts, cyanobacteria, which could bring this system into a plant cell is indicated.
Abstract: It was shown for the first time the presence of the soluble cytokinin-binding protein with a mol wt of 67 kD (CBP67) in the cyanobacterium Synechocysti sp. PCC 6803. CBP67 was isolated by two independent methods: by affinity chromatography on zeatin-Sepharose and by immunoaffinity chromatography on zeatin-Sepharose using monoclonal antibodies (mAb) raised against maize CBP70 (70 kD). The cytokinin-binding properties of CBP67 were assessed by its interaction with anti-idiotype Ab (Aba-i) raised against Ab to zeatin. Aba-i are, in fact, Ab to zeatin-binding site of the protein. The high specificity of interaction between trans-zeatin and CBP67 was demonstrated. Zeatin riboside and cis-zeatin mahifested a reduced interaction with CBP67; other phytohormones (auxin, gibberellic acid, and ABA) and adenine did not interact with the protein at all. Cyanobacterial CBP67 activated in vitro transcription in the Synechocystis lysate. The highest effect on transcription was observed at a combined action of CBP67 and trans-zeatin. Cyanobacterial CBP67 activated transcription in the barley chloroplast lysate as well. The totality of the results indicates a possibility of the existence of systems of cytokinin signal perception in the evolutionary precursor of chloroplasts, cyanobacteria, which could bring this system into a plant cell.
4 citations
TL;DR: Protoplasts were isolated from callus derived from excised cotyledons of stock by using an enzyme mixture of 1.5% Meicelase and 0.05% Macerozyme R-10 and developed to the callus-stage 2 months after initial culture.
Abstract: Protoplasts were isolated from callus derived from excised cotyledons of stock (Matthiola incana R. Br.), by using an enzyme mixture of 1.5% Meicelase and 0.05% Macerozyme R-10. Modified Murashige-Skoog major elements, Ringe and Nitsch minor elements and modified vitamins supplemented with 0.2mg/l 2, 4-D, 1mg/l NAA, 1mg/l BAP, 8.1% mannitol, 1% glucose and 1% sucrose supported protoplast division at 25°C. The frequency of colony formation 10 days after culture was the highest (17.9% of isolated protoplasts) at protoplast density of 0.5×105/ml. Colonies developed to the callus-stage 2 months after initial culture. When callus pieces were cultured in full strength MS medium supplemented with 1mg/l BAP or 1mg/l zeatin, adventitious buds were induced in 9%-16% of callus explants. The buds elongated with leaves open at 20°C and rooted in medium supplemented with 0.1mg/l or 5mg/l IBA.
4 citations
4 citations
TL;DR: Zeatin-9-riboside was identified in shoots and roots of Pinus resinosa by GC-MS analysis of its permethyl derivative, and the presence of equivalent amounts of [9R-5′P]iP in both the roots and shots suggests that cytokinin biosynthesis may be occurring in both locations.
Abstract: Zeatin-9-riboside was identified in shoots and roots of Pinus resinosa by GC-MS analysis of its permethyl derivative. Based on their chromatographic properties on Sephadex LH-20 and C18 HPLC, and their susceptibility to enzymatic degradation, several other cytokinins have been tentatively identified. The basic fraction of both the roots and shoots contained zeatin, whereas the shoots contained dihydrozeatin-O-glucoside and the roots contained zeatin-O-glucoside. Zeatin-9-riboside monophosphate, isopentenyladenosine monophosphate ([9R-5′P]iP) and glucosyl phosphate derivatives were detected in the acidic fractions from both roots and shoots. There were equivalent amounts of [9R-5′P]iP in both roots and shoots. The presence of equivalent amounts of [9R-5′P]iP in both the roots and shots suggests that cytokinin biosynthesis may be occurring in both locations.
4 citations
TL;DR: Tsen et al. as mentioned in this paper analyzed the effects of zeatin (ZT) and gibberellin A3 (GA3), and their interaction, on the bolting of Chinese cabbage.
Abstract: Flowering Chinese cabbage (Brassica campestris L. ssp. Chinensis var. utilis Tsen et Lee) is an important and extensively cultivated vegetable in south China, whose major food product is the stalk. In the process of stalk formation, its initiation and development are regulated by a series of hormonal signals, such as cytokinin and gibberellin. In this study, we analyzed the effects of zeatin (ZT) and gibberellin A3 (GA3), and their interaction, on the bolting of flowering Chinese cabbage. The results indicated that the three-true-leaf spraying of ZT and GA synthesis inhibitor (PAC) inhibited plant height but increased stem diameter. Cytokinin (CTK) synthesis inhibitor (YZJ) and GA3 treatment increased plant height and decreased stem diameter. In addition, ZT and GA3 co-treated plants displayed antagonistic effect. Further, 19 type-B authentic response regulators (ARR-Bs), the positive regulators of cytokinin signal transduction were identified from flowering Chinese cabbage. Comprehensive analysis of phylogeny showed BcARR-Bs clustered into three subfamilies with 10 conserved motifs. Analysis of their expression patterns in different tissues and at various growth stage, and their response to hormone treatment suggest that ARR1-b localized in the nucleus displayed unique highest expression patterns in stem tips, are responsive both to ZT and GA, suggesting a significant role in mediating the crosstalk of ZT and GA in the bolting of flowering Chinese cabbage.
4 citations