Gibberellin A1 is required for stem elongation in spinach.

Zeevaart, Jan A. D.; Gage, Douglas A.; Talón, Manuel

doi:10.1073/pnas.90.15.7401

Cited by 86 publications

(45 citation statements)

References 17 publications

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“…The procedures for extraction, purification, and quantification of endogenous GAs have been described elsewhere (Talon et al, 1990;Zeevaart et al, 1993;Schomburg et al, 2003).…”

Section: Analysis Of Endogenous Ga Levelsmentioning

confidence: 99%

A Novel Class of Gibberellin 2-Oxidases Control Semidwarfism, Tillering, and Root Development in Rice

et al. 2008

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Gibberellin 2-oxidases (GA2oxs) regulate plant growth by inactivating endogenous bioactive gibberellins (GAs). Two classes of GA2oxs inactivate GAs through 2b-hydroxylation: a larger class of C 19 GA2oxs and a smaller class of C 20 GA2oxs. In this study, we show that members of the rice (Oryza sativa) GA2ox family are differentially regulated and act in concert or individually to control GA levels during flowering, tillering, and seed germination. Using mutant and transgenic analysis, C 20 GA2oxs were shown to play pleiotropic roles regulating rice growth and architecture. In particular, rice overexpressing these GA2oxs exhibited early and increased tillering and adventitious root growth. GA negatively regulated expression of two transcription factors, O. sativa homeobox 1 and TEOSINTE BRANCHED1, which control meristem initiation and axillary bud outgrowth, respectively, and that in turn inhibited tillering. One of three conserved motifs unique to the C 20 GA2oxs (motif III) was found to be important for activity of these GA2oxs. Moreover, C 20 GA2oxs were found to cause less severe GA-defective phenotypes than C 19 GA2oxs. Our studies demonstrate that improvements in plant architecture, such as semidwarfism, increased root systems and higher tiller numbers, could be induced by overexpression of wild-type or modified C 20 GA2oxs.

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“…The procedures for extraction, purification, and quantification of endogenous GAs have been described elsewhere (Talon et al, 1990;Zeevaart et al, 1993;Schomburg et al, 2003).…”

Section: Analysis Of Endogenous Ga Levelsmentioning

confidence: 99%

A Novel Class of Gibberellin 2-Oxidases Control Semidwarfism, Tillering, and Root Development in Rice

et al. 2008

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“…Gibberellins activate cell division and cell enlargement processes in vegetative organs (Talon et al, 1991) and therefore are generally associated with the initiation of growth (Talon and Zeevaart, 1992). The endogenous GAs found in citrus fruits are mainly members of the 13-hydroxylation pathway [GA 53 , GA 97 , GA 44 , GA 17 , GA 19 , GA 20 , GA 29 , GA 1 , epi-GA 1 , and GA 8 (Goto et al, 1989;Turnbull, 1989;Talon et al, 1990a] leading to GA 1 , the bioactive GA (Zeevaart et al, 1993). This pathway also operates in vegetative tissues of citrus (Vidal et al, 2001(Vidal et al, , 2003 where is thought to control shoot growth and elongation (Fagoaga et al, 2007).…”

Section: Hormonal Regulators Of Fruit Growth and Abscissionmentioning

confidence: 99%

Physiology of citrus fruiting

Iglesias

Cercós

Colmenero‐Flores

et al. 2007

Braz. J. Plant Physiol.

306

232

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Citrus is the main fruit tree crop in the world and therefore has a tremendous economical, social and cultural impact in our society. In recent years, our knowledge on plant reproductive biology has increased considerably mostly because of the work developed in model plants. However, the information generated in these species cannot always be applied to citrus, predominantly because citrus is a perennial tree crop that exhibits a very peculiar and unusual reproductive biology. Regulation of fruit growth and development in citrus is an intricate phenomenon depending upon many internal and external factors that may operate both sequentially and simultaneously. The elements and mechanisms whereby endogenous and environmental stimuli affect fruit growth are being interpreted and this knowledge may help to provide tools that allow optimizing production and fruit with enhanced nutritional value, the ultimate goal of the Citrus Industry. This article will review the progress that has taken place in the physiology of citrus fruiting during recent years and present the current status of major research topics in this area. Key words: abiotic stresses, abscission, color break, flowering, fruit set, ripening Fisiologia da frutificação em citrus. Citrus é a principal fruteira no mundo, tendo, portanto, profundos impactos econômicos, sociais e culturais em nossa sociedade. Nos últimos anos, o conhecimento sobre a biologia reprodutiva de plantas tem aumentado consideravelmente, principalmente em função de trabalhos desenvolvidos com plantas-modelo. Todavia, a informação produzida nessas espécies nem sempre pode ser aplicada a citrus, fundamentalmente porque citrus é uma cultura arbórea perene com uma biologia reprodutiva muito peculiar e incomum. A regulação do crescimento e desenvolvimento do fruto em citrus é um fenômeno complexo e dependente de muitos fatores externos e internos que podem operar tanto seqüencialmente como simultaneamente. Os elementos e mecanismos pelos quais estímulos ambientes e endógenos afetam o crescimento do fruto vêm sendo interpretados, e esse conhecimento pode auxiliar a prover ferramentas que permitiriam otimizar a produção per se, além da obtenção de frutos com maior valor nutricional, o objetivo precípuo da Industria de Citrus. Neste artigo, revisam-se os avanços que vêm ocorrendo na fisiologia da frutificação de citrus durante os últimos anos; apresenta-se, também, o status atual de pesquisas mais relevantes nessa área. Palavras-chave: estresses abióticos, floração, maturação, vingamento de frutos

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“…This is also true of spinach (Metzger and Zeevaart 1982), in which the conversion of GA 53 to GA 44 and of GA 19 to GA 20 are both regulated by daylength (Talon et al 1991). In addition, an earlier step in biosynthesis of ent-kaurene is also regulated by daylength (Zeevaart et al 1993). Wu et al (1996) subsequently showed that the level of GA 20 -oxidase mRNA is higher in plants in LD.…”

Section: Stem Elongation and Floweringmentioning

confidence: 83%

Gibberellins and flowering in long day plants, with special reference to Lolium temulentum

Evans¹

1999

Functional Plant Biol.

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Abstract. The relation between gibberellins (GAs) and flowering in some long day (LD) plants is reviewed, with particular emphasis on Lolium temulentum. Lang s early experiments with rosette plants established the effectiveness of several GAs in replacing the need for LD. Subsequent work with mutants, especially of Arabidopsis, has clarified genetic and environmental control points in GA synthesis, various feedback effects and some of the factors affecting responsiveness to, as well as synthesis of, GAs in the flowering process. Further complexities are revealed in the experiments with Lolium temulentum, which have clearly shown that the structural requirements for effectiveness of GAs in the flowering process are quite different from those for elongation growth. The precise role of GAs in the long day induction of flowering remains unclear.

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Gibberellin A1 is required for stem elongation in spinach.

Cited by 86 publications

References 17 publications

A Novel Class of Gibberellin 2-Oxidases Control Semidwarfism, Tillering, and Root Development in Rice

A Novel Class of Gibberellin 2-Oxidases Control Semidwarfism, Tillering, and Root Development in Rice

Physiology of citrus fruiting

Gibberellins and flowering in long day plants, with special reference to Lolium temulentum

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