scispace - formally typeset
Search or ask a question
Topic

Gibberellic acid

About: Gibberellic acid is a research topic. Over the lifetime, 6597 publications have been published within this topic receiving 109294 citations. The topic is also known as: GIBBERELLIN A3.


Papers
More filters
Journal ArticleDOI
TL;DR: The isolation of three potato cDNA clones encoding GA 20-oxidase, a key regulatory enzyme in the GA-biosynthetic pathway, is reported, which suggests that night-break induction of this gene might play a role in the control of tuberization by regulating endogenous levels of GAs in response to daylength conditions.
Abstract: Tuber formation in potato (Solanum tuberosum) is promoted by short photoperiods and is inhibited by gibberellins (GAs). Endogenous levels of GA1 were shown to decrease in stolons and leaves of potato plants induced to tuberize, which suggests that photoperiodic regulation of GA biosynthesis may play a role in tuber induction. We report the isolation of three potato cDNA clones (StGA20ox1–3) encoding GA 20-oxidase, a key regulatory enzyme in the GA-biosynthetic pathway. Using northern analysis, we detected a differential pattern of tissue-specific expression of the mRNAs corresponding to these clones. StGA20ox mRNAs were also very abundant in leaves of the potato ga1 mutant, which is blocked in the 13-hydroxylation step, and were strongly down-regulated by gibberellic acid, suggesting a feedback regulation of these genes. In plants grown in short-day (inductive) conditions, levels of the StGA20ox transcripts in leaves fluctuated during a 24-h period, with a peak of accumulation observed about 4 h after the lights were turned off. Interruption of the night with a 30-min “night break” of light (noninductive conditions) did not have a marked effect on the levels of accumulation of the three GA 20-oxidase mRNAs during the day, but it induced a second peak of expression of StGA20ox1 and StGA20ox3 transcripts late in the night. This observation, together with the finding that StGA20ox1 mRNA is expressed at high levels in leaves, suggests that night-break induction of this gene might play a role in the control of tuberization by regulating endogenous levels of GAs in response to daylength conditions.

96 citations

Journal ArticleDOI
TL;DR: In situ mRNA hybridization analysis in sections obtained from fungus-infected germinating embryos revealed that ZmPR4 mRNA accumulation occurs in those cell types that first establish contact with the pathogen, and could be part of the general defence response of maize plants against pathogens.
Abstract: Pathogenesis-related (PR) proteins are plant proteins that are induced in response to pathogen attack. PR proteins are grouped into independent families based on their sequences and properties. The PR-4 family comprises class I and class II chitinases. We have isolated a full-length cDNA encoding a chitinase from maize which shares a high degree of nucleotide and amino acid sequence homology with the class II chitinases of the PR-4 family of PR proteins. Our results indicate that fungal infection, and treatment either with fungal elicitors or with moniliformin, a mycotoxin produced by the fungus Fusarium moniliforme, increase the level of ZmPR4 mRNA. In situ mRNA hybridization analysis in sections obtained from fungus-infected germinating embryos revealed that ZmPR4 mRNA accumulation occurs in those cell types that first establish contact with the pathogen. ZmPR4 mRNA accumulation is also stimulated by treatment with silver nitrate whereas the application of the hormones gibberellic acid or acetylsalicylic acid has no effect. Wounding, or treatment with abscisic acid or methyl jasmonate, results in accumulation of ZmPR4 mRNA in maize leaves. Furthermore, the ZmPR4 protein was expressed in Escherichia coli, purified and used to obtain polyclonal antibodies that specifically recognized ZmPR4 in protein extracts from fungus-infected embryos. Accumulation of ZmPR4 mRNA in fungus-infected maize tissues was accompanied by a significant accumulation of the corresponding protein. The possible implications of these findings as part of the general defence response of maize plants against pathogens are discussed.

96 citations

Journal ArticleDOI
TL;DR: The role of various growth-regulating substances in tuberization in Solarium andigena was studied by application of exogenous growth regulators, and by studying variation in the levels of endogenous hormones under tuber-inducing and non-inducing conditions.
Abstract: Summary The role of various growth-regulating substances in tuberization in Solarium andigena was studied (1) by application of exogenous growth regulators, and (2) by studying variation in the levels of endogenous hormones under tuber-inducing and non-inducing conditions In short-day induced cuttings tuberization was inhibited by gibberellic acid; indole acetic acid and kinetin (6-furfuryl amino purine) caused slight stimulation of tuber growth at low concentrations, but inhibited it at higher concentrations Application of (2-chloroethyl) trimethyl-ammonium chloride (CCC) promoted tuberization in plants growing under non-inducing long-day conditions and in buds produced on isolated plugs of tuber tissue The tuber-inducing effects of CCC were not reversed by simultaneous application of GA3 Levels of endogenous gibberellins decreased markedly under short-day conditions, but there was no difference in the levels of endogenous abscisic acid under long and short days The reduced levels of gibberellins were maintained for at least 2 weeks when induced plants were transferred from short-day to long-day conditions Application of CCC under conditions which promoted tuberization caused a reduction in gibberellin levels The role of growth hormones in the regulation of tuberization is discussed

96 citations

Journal ArticleDOI
TL;DR: It is proposed that OsNAC2 is a negative regulator of the plant height and flowering time, which acts by directly regulating key genes of the GA pathway in rice.
Abstract: Summary Plant height and flowering time are key agronomic traits affecting yield in rice (Oryza sativa). In this study, we investigated the functions in rice growth and development of OsNAC2, encoding a NAC transcription factor in rice. Transgenic plants that constitutively expressed OsNAC2 had shorter internodes, shorter spikelets, and were more insensitive to gibberellic acid (GA3). In addition, the levels of GAs decreased in OsNAC2 overexpression plants, compared with the wild-type. Moreover, flowering was delayed for approximately 5 days in transgenic lines. The transcription of Hd3a, a flowering-time related gene, was suppressed in transgenic lines. In addition, transgenic Arabidopsis plants expressing OsNAC2 were also more insensitive to GA3. The expression levels of GA biosynthetic genes OsKO2 and OsKAO were repressed. The expression of OsSLRL, encoding a repressor in the GA signal pathway, and OsEATB, which encodes a repressor of GA biosynthesis, were both enhanced. Western blotting indicated that DELLA also accumulated at the protein level. Dual-luciferase reporter analyses, yeast one-hybrid assays and ChIP-qPCR suggested that OsNAC2 directly interacted with the promoter of OsEATB and OsKO2. Taken together, we proposed that OsNAC2 is a negative regulator of the plant height and flowering time, which acts by directly regulating key genes of the GA pathway in rice.

96 citations

Journal ArticleDOI
TL;DR: Results of gene expression analysis indicate that AtTZF4, 5 and 6 affect seed germination by controlling genes critical for ABA and GA response and can co-localize with both PB and SG markers in Arabidopsis cells.
Abstract: Tandem CCCH zinc finger proteins (TZFs) are post-transcriptional regulators of gene expression in animals and yeast. Genetic studies indicate that plant TZFs are involved in hormone-mediated developmental and environmental responses. We have demonstrated previously that Arabidopsis AtTZF1 can localize to processing bodies (PBs) and stress granules (SGs), and affects abscisic acid (ABA)- and gibberellic acid (GA)-mediated growth, stress and gene expression responses. Here we show that AtTZF4, 5 and 6 are specifically expressed in seeds. Consistent with the observation that their expression levels decline during seed imbibition, AtTZF4, 5 and 6 are up-regulated by ABA and down-regulated by GA. Mutant analyses indicate that AtTZF4, 5 and 6 act as positive regulators for ABA- and negative regulators for light- and GA-mediated seed germination responses. Results of gene expression analysis indicate that AtTZF4, 5 and 6 affect seed germination by controlling genes critical for ABA and GA response. Furthermore, AtTZF4, 5 and 6 can co-localize with both PB and SG markers in Arabidopsis cells. Specifically, AtTZF6 can be assembled into PBs and SGs in embryos with the induction of stress hormone methyl jasmonate under the control of native AtTZF6 promoter.

96 citations


Network Information
Related Topics (5)
Shoot
32.1K papers, 693.3K citations
94% related
Germination
51.9K papers, 877.9K citations
91% related
Auxin
10.7K papers, 502.6K citations
91% related
Seedling
28.6K papers, 478.2K citations
88% related
Abscisic acid
12.8K papers, 587K citations
88% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023203
2022406
2021133
2020153
2019165
2018196