Inhibitory effects of elevated endogenous cytokinins on nitrate reductase in ipt-expressing tobacco are eliminated by short-term exposure to benzyladenine

LEXA, Matej, Todor Nikolaev GENKOV and Břetislav BRZOBOHATÝ. Inhibitory effects of elevated endogenous cytokinins on nitrate reductase in ipt-expressing tobacco are eliminated by short-term exposure to benzyladenine. PHYSIOLOGIA PLANTARUM. Copenhagen: Munksgaard, 2002, vol. 115, No 2, p. 284-290. ISSN 0031-9317.

Basic information

• Original name: Inhibitory effects of elevated endogenous cytokinins on nitrate reductase in ipt-expressing tobacco are eliminated by short-term exposure to benzyladenine
• Authors: LEXA, Matej (703 Slovakia), Todor Nikolaev GENKOV (100 Bulgaria) and Břetislav BRZOBOHATÝ (203 Czech Republic, guarantor).
• Edition: PHYSIOLOGIA PLANTARUM, Copenhagen, Munksgaard, 2002, 0031-9317.

Other information

• Original language: English
• Type of outcome: Article in a journal
• Field of Study: 10600 1.6 Biological sciences
• Country of publisher: Czech Republic
• Confidentiality degree: is not subject to a state or trade secret
• Impact factor: Impact factor: 1.565
• RIV identification code: RIV/00216224:14330/02:00005604
• Organization unit: Faculty of Informatics
• UT WoS: 000176344700015
• Keywords in English: cytokinins; Dianthus caryophyllus; 4-pu-30; thidiazuron; photosystem II; chlorophyll fluorescence; delayed fluorescence; heat-induced changes; gas-exchange; photosynthetic response; cytokinin activity; high-temperature; plant-growth; in-vitro; accumulation; adaptation; cotyledons.
• Tags: 4-PU-30, accumulation, adaptation, chlorophyll fluorescence, cotyledons., cytokinin activity, cytokinins, delayed fluorescence, Dianthus caryophyllus, gas-exchange, heat-induced changes, high-temperature, in-vitro, photosynthetic response, photosystem II, plant-growth, thidiazuron
• Tags: International impact, Reviewed

Abstract

Using a novel system for expressing ipt gene from Agrobacterium tumefaciens in tobacco (Nicotiana tabacum L., cv. Petit Havana SR1), we were able to grow seedlings and teratoma-like tissue with increased content of cytokinins. This material enabled us to investigate new regulatory aspects of nitrate reduction. We had grown control plants and plants with elevated cytokinins on MS media with or without nitrate and benzyladenine (BA). We determined in vitro nitrate reductase (E.C. 1.6.6.1) activity (NRA) in this plant material. Initially, we found that ipt-expressing plants always displayed lowered levels of NRA when compared to wild-type SR1 plants. We determined that long-term exposure of tobacco plants and tissue to cytokinins caused up to 60% decrease in NRA. Exposure to 40 mM nitrate was able to induce the activity in such plants 3-fold, increasing the activity in SR1 plants more than 5-fold. We were able to restore wild-type levels of NRA in ipt-expressing plants by simultaneous induction of NR with BA and nitrate. Our results suggest that regulation of NR by nitrate and cytokinin is a result of overlaying cytokinin-driven regulatory processes, with those acting in short-term having positive effect on NRA and those acting over extended periods of time having inhibitory effects on NRA.

Links

• IAA5004001, research and development project: Name: Systém aktivace transkripce pro studium vztahu mezi metabolizmem a účinkem cytokininů u Arabidopsis a tabáku

Investor: Academy of Sciences of the Czech Republic, Transkription activation system for studying the relationship between cytokinin metabolism and action in Arabidopsis and tobacco

• MSM 143100008, plan (intention): Name: Genomy a jejich funkce

Investor: Ministry of Education, Youth and Sports of the CR, Genomes and their functions

• VS96096, research and development project: Name: Laboratoř molekulární fyziologie rostlin

Investor: Ministry of Education, Youth and Sports of the CR, Laboratory of Molecular Plant Physiology