ACC Treatment (acc + treatment)

Distribution by Scientific Domains
Life Sciences100%

Selected Abstracts

Enhanced expression of genes for ACC synthase, ACC oxidase, and NAC protein during high-temperature-induced necrosis of young inflorescences of Cymbidium

PHYSIOLOGIA PLANTARUM, Issue 3 2006
Satoru Mita
Growing Cymbidium under high-temperature conditions (25,30°C) results in the necrosis of young inflorescences. An increase in the evolution of ethylene was correlated with the necrosis. To study the molecular aspects of high-temperature-induced necrosis of Cymbidium floral buds, we isolated complementary DNA (cDNA) clones for proteins that are likely to be involved in the biosynthesis of ethylene during high-temperature-induced necrosis of young inflorescences, namely, 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (CyACS1) and ACC oxidase (CyACO1). In addition, a cDNA (CyNAC1) encoding an NAC protein whose expression is modulated during high-temperature treatment was isolated by differential display. High levels of expression of CyACS1, CyACO1 and CyNAC1 were observed in the necrotic inflorescences of wild-type Cymbidium at high temperatures. Bud necrosis was not observed in the mericlone mutant (nhn, non,high-temperature-induced necrosis) of Cymbidium. Ethylene evolution was lower in nhn than in wild-type, but application of exogenous ACC or ethephon to the young inflorescences of nhn restored the high-temperature necrosis response. Expression of CyACS1, CyACO1 and CyNAC1 did not increase with high-temperature treatment in the nhn mutant. Expression levels of CyACS1, CyACO1 and CyNAC1 in necrotic inflorescences of nhn treated with 5.0 mM ACC were much lower than in necrotic inflorescences of wild-type at high temperatures, but CyACS1 and CyNAC1 were stimulated by ACC treatment. These results suggest that ethylene is involved in high-temperature necrosis of young inflorescences of Cymbidium and that an NAC protein may be involved in the regulatory mechanisms of genes that are regulated during necrosis. [source]

Genetic dissection of the role of ethylene in regulating auxin-dependent lateral and adventitious root formation in tomato

THE PLANT JOURNAL, Issue 1 2010
Sangeeta Negi
Summary In this study we investigated the role of ethylene in the formation of lateral and adventitious roots in tomato (Solanum lycopersicum) using mutants isolated for altered ethylene signaling and fruit ripening. Mutations that block ethylene responses and delay ripening ,Nr (Never ripe), gr (green ripe), nor (non ripening), and rin (ripening inhibitor) , have enhanced lateral root formation. In contrast, the epi (epinastic) mutant, which has elevated ethylene and constitutive ethylene signaling in some tissues, or treatment with the ethylene precursor 1-aminocyclopropane carboxylic acid (ACC), reduces lateral root formation. Treatment with ACC inhibits the initiation and elongation of lateral roots, except in the Nr genotype. Root basipetal and acropetal indole-3-acetic acid (IAA) transport increase with ACC treatments or in the epi mutant, while in the Nr mutant there is less auxin transport than in the wild type and transport is insensitive to ACC. In contrast, the process of adventitious root formation shows the opposite response to ethylene, with ACC treatment and the epi mutation increasing adventitious root formation and the Nr mutation reducing the number of adventitious roots. In hypocotyls, ACC treatment negatively regulated IAA transport while the Nr mutant showed increased IAA transport in hypocotyls. Ethylene significantly reduces free IAA content in roots, but only subtly changes free IAA content in tomato hypocotyls. These results indicate a negative role for ethylene in lateral root formation and a positive role in adventitious root formation with modulation of auxin transport as a central point of ethylene,auxin crosstalk. [source]

Ethylene regulates lateral root formation and auxin transport in Arabidopsis thaliana

THE PLANT JOURNAL, Issue 2 2008
Sangeeta Negi
Summary Lateral root branching is a genetically defined and environmentally regulated process. Auxin is required for lateral root formation, and mutants that are altered in auxin synthesis, transport or signaling often have lateral root defects. Crosstalk between auxin and ethylene in root elongation has been demonstrated, but interactions between these hormones in the regulation of Arabidopsis lateral root formation are not well characterized. This study utilized Arabidopsis mutants altered in ethylene signaling and synthesis to explore the role of ethylene in lateral root formation. We find that enhanced ethylene synthesis or signaling, through the eto1-1 and ctr1-1 mutations, or through the application of 1-aminocyclopropane-1-carboxylic acid (ACC), negatively impacts lateral root formation, and is reversible by treatment with the ethylene antagonist, silver nitrate. In contrast, mutations that block ethylene responses, etr1-3 and ein2-5, enhance root formation and render it insensitive to the effect of ACC, even though these mutants have reduced root elongation at high ACC doses. ACC treatments or the eto1-1 mutation significantly enhance radiolabeled indole-3-acetic acid (IAA) transport in both the acropetal and the basipetal directions. ein2-5 and etr1-3 have less acropetal IAA transport, and transport is no longer regulated by ACC. DR5-GUS reporter expression is also altered by ACC treatment, which is consistent with transport differences. The aux1-7 mutant, which has a defect in an IAA influx protein, is insensitive to the ethylene inhibition of root formation. aux1-7 also has ACC-insensitive acropetal and basipetal IAA transport, as well as altered DR5-GUS expression, which is consistent with ethylene altering AUX1-mediated IAA uptake, and thereby blocking lateral root formation. [source]

Genetic dissection of the role of ethylene in regulating auxin-dependent lateral and adventitious root formation in tomato

THE PLANT JOURNAL, Issue 1 2010
Sangeeta Negi
Summary In this study we investigated the role of ethylene in the formation of lateral and adventitious roots in tomato (Solanum lycopersicum) using mutants isolated for altered ethylene signaling and fruit ripening. Mutations that block ethylene responses and delay ripening ,Nr (Never ripe), gr (green ripe), nor (non ripening), and rin (ripening inhibitor) , have enhanced lateral root formation. In contrast, the epi (epinastic) mutant, which has elevated ethylene and constitutive ethylene signaling in some tissues, or treatment with the ethylene precursor 1-aminocyclopropane carboxylic acid (ACC), reduces lateral root formation. Treatment with ACC inhibits the initiation and elongation of lateral roots, except in the Nr genotype. Root basipetal and acropetal indole-3-acetic acid (IAA) transport increase with ACC treatments or in the epi mutant, while in the Nr mutant there is less auxin transport than in the wild type and transport is insensitive to ACC. In contrast, the process of adventitious root formation shows the opposite response to ethylene, with ACC treatment and the epi mutation increasing adventitious root formation and the Nr mutation reducing the number of adventitious roots. In hypocotyls, ACC treatment negatively regulated IAA transport while the Nr mutant showed increased IAA transport in hypocotyls. Ethylene significantly reduces free IAA content in roots, but only subtly changes free IAA content in tomato hypocotyls. These results indicate a negative role for ethylene in lateral root formation and a positive role in adventitious root formation with modulation of auxin transport as a central point of ethylene,auxin crosstalk. [source]

Ethylene regulates lateral root formation and auxin transport in Arabidopsis thaliana

THE PLANT JOURNAL, Issue 2 2008
Sangeeta Negi
Summary Lateral root branching is a genetically defined and environmentally regulated process. Auxin is required for lateral root formation, and mutants that are altered in auxin synthesis, transport or signaling often have lateral root defects. Crosstalk between auxin and ethylene in root elongation has been demonstrated, but interactions between these hormones in the regulation of Arabidopsis lateral root formation are not well characterized. This study utilized Arabidopsis mutants altered in ethylene signaling and synthesis to explore the role of ethylene in lateral root formation. We find that enhanced ethylene synthesis or signaling, through the eto1-1 and ctr1-1 mutations, or through the application of 1-aminocyclopropane-1-carboxylic acid (ACC), negatively impacts lateral root formation, and is reversible by treatment with the ethylene antagonist, silver nitrate. In contrast, mutations that block ethylene responses, etr1-3 and ein2-5, enhance root formation and render it insensitive to the effect of ACC, even though these mutants have reduced root elongation at high ACC doses. ACC treatments or the eto1-1 mutation significantly enhance radiolabeled indole-3-acetic acid (IAA) transport in both the acropetal and the basipetal directions. ein2-5 and etr1-3 have less acropetal IAA transport, and transport is no longer regulated by ACC. DR5-GUS reporter expression is also altered by ACC treatment, which is consistent with transport differences. The aux1-7 mutant, which has a defect in an IAA influx protein, is insensitive to the ethylene inhibition of root formation. aux1-7 also has ACC-insensitive acropetal and basipetal IAA transport, as well as altered DR5-GUS expression, which is consistent with ethylene altering AUX1-mediated IAA uptake, and thereby blocking lateral root formation. [source]