Light- and phytohormone-induced variations in the level and modified nucleotide content of plastid tRNAs

Jayabaskaran, Chelliah

doi:10.1016/s0168-9452(97)00246-x

Cited by 3 publications

(4 citation statements)

References 38 publications

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“…The decrease in RNA level is observed in algal cells grown in the complete darkness. Numerous subsequent studies have shown that low-light intensities or darkness result in the reduced expression light dependent genes; stimulate RNAse activity and RNA degradation (Thomas et al 1997;Jayabaskaran 1998). Moreover, treating dark-grown Chlorella vulgaris with cytokinins overrides the requirement of light for RNA synthesis and accumulation.…”

Section: Discussionmentioning

confidence: 99%

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Cellular response of light/dark-grown green alga Chlorella vulgaris Beijerinck (Chlorophyceae) to exogenous adenine- and phenylurea-type cytokinins

Piotrowska

Czerpak

2009

Acta Physiol Plant

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Treatment exposed to light Chlorella vulgaris Beijerinck (Chlorophyceae) with adenine-(BA, Kin, Z) and phenylurea-type (DPU) cytokinins effects positively on alga viability by 1.5-to twofold increase in cell number, chlorophylls, carotenoids, monosaccharides and glycolate content as well as NADH-dependent hydroxypyruvate reducing enzyme activity (NADH-HPR) extensively involved in carbon metabolism. Cytokinins enhance nitrogen assimilation by stimulation of NADH-dependent glutamate dehydrogenase (NADH-GDH) aminating activity finally leading to higher protein level and its secretion as well as polypeptide accumulation in the range of molecular weight 12-195 kDa. In the dark, cytokinins mimic the regulatory effect of light upon algal cell division, metabolite content and stimulate carbon recycling for Calvin cycle reactions by enhancing of light-dependent NADH-HPR activity. The delaying of protein degradation and stimulation of their secretion to environment, triggering polypeptide accumulation and twofold higher NADH-GDH activity catalysing amino acids biosynthesis are observed in the dark-grown microalgae in response to cytokinins. Chlorella vulgaris exhibits sensitivity on cytokinins in the following order of their stimulating properties: DPU [ Z [ Kin [ BA in both light and dark conditions. Understanding of cytokinin role in lower plants under different light conditions could be a step toward the elucidation of the evolution of hormone regulation and their action at molecular level.

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Section: Discussionmentioning

confidence: 99%

“…In many cases cytokinins replace light in induction of synthesis of some light-dependent proteins, e.g. chalcone synthase, phenylalanine ammonia lyase, chlorophyll a/b binding protein (Chin-Atkins et al 1996;Jayabaskaran 1998). Protein synthesis requires amino acids supplies which are synthesised after nitrates absorption and reduction.…”

Section: Discussionmentioning

confidence: 99%

Cellular response of light/dark-grown green alga Chlorella vulgaris Beijerinck (Chlorophyceae) to exogenous adenine- and phenylurea-type cytokinins

Piotrowska

Czerpak

2009

Acta Physiol Plant

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“…Not only nucleotide metabolism but also RNA synthesis and DNA repair processes exhibit light and redox dependency ( Table A3 ). The presence of light can alter the nucleotide content of tRNAs [ 207 ]. Plastid-encoded RNA polymerase (PEP) is a principal RNA polymerase in chloroplasts and is affected by light-induced redox signals [ 201 ].…”

Section: Light Intensity- and Spectrum-associated Adjustment Of Metab...mentioning

confidence: 99%

Light Intensity- and Spectrum-Dependent Redox Regulation of Plant Metabolism

et al. 2022

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Both light intensity and spectrum (280–800 nm) affect photosynthesis and, consequently, the formation of reactive oxygen species (ROS) during photosynthetic electron transport. ROS, together with antioxidants, determine the redox environment in tissues and cells, which in turn has a major role in the adjustment of metabolism to changes in environmental conditions. This process is very important since there are great spatial (latitude, altitude) and temporal (daily, seasonal) changes in light conditions which are accompanied by fluctuations in temperature, water supply, and biotic stresses. The blue and red spectral regimens are decisive in the regulation of metabolism because of the absorption maximums of chlorophylls and the sensitivity of photoreceptors. Based on recent publications, photoreceptor-controlled transcription factors such as ELONGATED HYPOCOTYL5 (HY5) and changes in the cellular redox environment may have a major role in the coordinated fine-tuning of metabolic processes during changes in light conditions. This review gives an overview of the current knowledge of the light-associated redox control of basic metabolic pathways (carbon, nitrogen, amino acid, sulphur, lipid, and nucleic acid metabolism), secondary metabolism (terpenoids, flavonoids, and alkaloids), and related molecular mechanisms. Light condition-related reprogramming of metabolism is the basis for proper growth and development of plants; therefore, its better understanding can contribute to more efficient crop production in the future.

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“…Lower levels were reported not only of chlorophyll a / b content but also of cell quantity, RNA content, and protein content in algal cells grown in complete darkness compared with those grown under light (Piotrowska & Czerpak, ). Furthermore, it was demonstrated that low‐light intensities and darkness reduced expression in light‐dependent genes, and that darkness stimulated RNase activity and RNA degeneration (Thomas et al ., ; Jayabaskaran, ). Regarding the algal resistance to the host lysosomal enzymes, a previous study reported that live algae can delay the digestion of dead algae when both algae have been ingested in the same DV (Karakashian & Karakashian, ).…”

Section: Resultsmentioning

confidence: 99%

SymbioticChlorella variabilisincubated under constant dark conditions for 24 hours loses the ability to avoid digestion by host lysosomal enzymes in digestive vacuoles of host ciliateParamecium bursaria

Kodama

Fujishima

2014

FEMS Microbiology Ecology

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Endosymbiosis between symbiotic Chlorella and alga-free Paramecium bursaria cells can be induced by mixing them. To establish the endosymbiosis, algae must acquire temporary resistance to the host lysosomal enzymes in the digestive vacuoles (DVs). When symbiotic algae isolated from the alga-bearing paramecia are kept under a constant dark conditions for 24 h before mixing with the alga-free paramecia, almost all algae are digested in the host DVs. To examine the cause of algal acquisition to the host lysosomal enzymes, the isolated algae were kept under a constant light conditions with or without a photosynthesis inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea for 24 h, and were mixed with alga-free paramecia. Unexpectedly, most of the algae were not digested in the DVs irrespective of the presence of the inhibitor. Addition of 1 mM maltose, a main photosynthetic product of the symbiotic algae or of a supernatant of the isolated algae kept for 24 h under a constant light conditions, did not rescue the algal digestion in the DVs. These observations reveal that unknown factors induced by light are a prerequisite for algal resistance to the host lysosomal enzymes.

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Light- and phytohormone-induced variations in the level and modified nucleotide content of plastid tRNAs

Cited by 3 publications

References 38 publications

Cellular response of light/dark-grown green alga Chlorella vulgaris Beijerinck (Chlorophyceae) to exogenous adenine- and phenylurea-type cytokinins

Cellular response of light/dark-grown green alga Chlorella vulgaris Beijerinck (Chlorophyceae) to exogenous adenine- and phenylurea-type cytokinins

Light Intensity- and Spectrum-Dependent Redox Regulation of Plant Metabolism

SymbioticChlorella variabilisincubated under constant dark conditions for 24 hours loses the ability to avoid digestion by host lysosomal enzymes in digestive vacuoles of host ciliateParamecium bursaria

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