Effect of growth-promoting chemicals on growth, nitrogen fixation and heterocyst frequency of a blue-green alga

Kapoor, K.; Sharma, Varsha

doi:10.1002/jobm.3630210406

Cited by 5 publications

(5 citation statements)

References 7 publications

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“…The influence of cytokinins on chloroplast development might also have its origin in an early function for cytokinins in cyanobacteria. Indeed, cytokinins stimulate pigment formation and nitrogen fixation in Anabaena (Kapoor and Sharma 1981).…”

Section: Cloning Of Ckx Genesmentioning

confidence: 99%

Structure and function of cytokinin oxidase/dehydrogenase genes of maize, rice, Arabidopsis and other species

et al. 2003

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Cytokinin oxidases/dehydrogenases (CKX) catalyze the irreversible degradation of the cytokinins isopentenyladenine, zeatin, and their ribosides in a single enzymatic step by oxidative side chain cleavage. To date the sequences of 17 fully annotated CKX genes are known, including two prokaryotic genes. The CKX gene families of Arabidopsis thaliana and rice comprise seven and at least ten members, respectively. The main features of CKX genes and proteins are summarized in this review. Individual proteins differ in their catalytic properties, their subcellular localization and their expression domains. The evolutionary development of cytokinin-catabolizing gene families and the individual properties of their members indicate an important role for the fine-tuned control of catabolism to assure proper regulation of cytokinin functions. The use of CKX genes as a tool in studies of cytokinin biology and biotechnological applications is discussed.

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Section: Cloning Of Ckx Genesmentioning

confidence: 99%

Structure and function of cytokinin oxidase/dehydrogenase genes of maize, rice, Arabidopsis and other species

et al. 2003

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“…Cyanobacteria, on the other hand, show responses to external addition of cytokinins such as growth promotion (Kapoor and Sharma, 1981;Suzuki et al, 2004) and enhanced transcription (Selivankina et al, 2006). It is therefore reasonable to expect that there exists a signalling pathway different from the one known in plants.…”

Section: Has Cytokinin Metabolism In Plants Evolved From Cyanobacteria?mentioning

confidence: 99%

Evolution of cytokinin biosynthesis and degradation

Frébort

Kowalska

Hluska

et al. 2011

Journal of Experimental Botany

351

283

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Cytokinin hormones are important regulators of development and environmental responses of plants that execute their action via the molecular machinery of signal perception and transduction. The limiting step of the whole process is the availability of the hormone in suitable concentrations in the right place and at the right time to interact with the specific receptor. Hence, the hormone concentrations in individual tissues, cells, and organelles must be properly maintained by biosynthetic and metabolic enzymes. Although there are merely two active cytokinins, isopentenyladenine and its hydroxylated derivative zeatin, a variety of conjugates they may form and the number of enzymes/isozymes with varying substrate specificity involved in their biosynthesis and conversion gives the plant a variety of tools for fine tuning of the hormone level. Recent genome-wide studies revealed the existence of the respective coding genes and gene families in plants and in some bacteria. This review summarizes present knowledge on the enzymes that synthesize cytokinins, form cytokinin conjugates, and carry out irreversible elimination of the hormones, including their phylogenetic analysis and possible variations in different organisms.

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“…Exogenous application of cytokinins to cultures of green algae has been shown to increase their growth rate, cell division, elongation, reproduction, and respiratory rate (Mooney and Van Staden 1986). The addition of cytokinins to blue‐green algal cultures promoted their growth, the synthesis of pigments, and nitrogen fixation (Kapoor and Sharma 1981). Cytokinins also have been reported to initiate the differentiation of mosses (Saunders and Hepler 1983).…”

Section: Discussionmentioning

confidence: 99%

Synthesis of the photorespiratory key enzyme serine: glyoxylate aminotransferase in C. reinhardtii is modulated by the light regime and cytokinin

Tian

Wang

Zhu

et al. 2006

Physiologia Plantarum

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Serine:glyoxylate aminotransferase (SGAT) is a key enzyme of photorespiration. Changes in SGAT transcript levels and in enzyme activity following shifts from light to dark or dark to light and after cultivation in media supplemented with 6‐benzyladenine (6‐BA), a synthetic cytokinin, were analysed in the green alga Chlamydomonas reinhardtii. Cells grown in darkness had higher transcript levels than those grown in the light and transcript levels decreased upon transfer of cultures from dark to light; in contrast, they increased upon shift from light to dark. However, higher enzyme activities were detected in light‐grown vs. dark‐grown cells, which could be correlated with an elevated photorespiratory activity of the light‐grown cultures. Application of the synthetic cytokinin into the medium promoted both the accumulation of SGAT mRNA and enhanced SGAT enzyme activity. Under these conditions an accelerated multiplication of cells as well as higher final cell densities were observed. However, the synthetic cytokinin did not affect chlorophyll content, which is different from cytokinin effects observed in higher plants. The presence of cytokinin‐like activities in C. reinhardtii was confirmed using high‐performance liquid chromatography. One of these activities was identified by mass‐spectroscopy to be zeatin riboside.

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Effect of growth-promoting chemicals on growth, nitrogen fixation and heterocyst frequency of a blue-green alga

Cited by 5 publications

References 7 publications

Structure and function of cytokinin oxidase/dehydrogenase genes of maize, rice, Arabidopsis and other species

Structure and function of cytokinin oxidase/dehydrogenase genes of maize, rice, Arabidopsis and other species

Evolution of cytokinin biosynthesis and degradation

Synthesis of the photorespiratory key enzyme serine: glyoxylate aminotransferase in C. reinhardtii is modulated by the light regime and cytokinin

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