Gibberellin 2‐oxidation and the SLN gene of Pisum sativum

Lester, Diane R.; Ross, John J.; Smith, Jennifer J.; Elliott, Robert C.; Reid, James B.

doi:10.1046/j.1365-313x.1999.00501.x

Cited by 121 publications

(115 citation statements)

References 29 publications

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“…The pronounced effect of long1 on the length of the first two internodes is most similar to that of the constitutive GA-response double DELLA mutant la cry-s (Potts et al, 1985;Weston et al, 2008) and the GA-overproducing sln mutant, which has a mutation in the GA catabolism gene GA2ox1 (Reid et al, 1992;Lester et al, 1999) (Figures 1A and 1B). By contrast, the phyB mutant, although equivalently elongated over later internodes, has only a weak effect on elongation of early internodes (Figures 1A and (A), (B), and (E) Phenotypes of elongated mutant seedlings under glasshouse conditions.…”

Section: Shoot Phenotype Of the Long1 Mutantmentioning

confidence: 64%

“…GA3ox genes catalyze the conversion of inactive GA 20 to the active form GA 1 , whereas the GA2ox genes convert GA 1 to the inactive product GA 8 ( Figure 5A). GA2ox1 but not GA2ox2 also has the ability to convert GA 20 to another inactive product GA 29 (Lester et al, 1999). Figure 5D shows that the clearest effect of light was seen for GA2ox2.…”

Section: Long1 Mediates the Rapid Effects Of Light On Ga Economymentioning

confidence: 97%

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Light Regulation of Gibberellin Biosynthesis in Pea Is Mediated through the COP1/HY5 Pathway

et al. 2009

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Light regulation of gibberellin (GA) biosynthesis occurs in several species, but the signaling pathway through which this occurs has not been clearly established. We have isolated a new pea (Pisum sativum) mutant, long1, with a light-dependent elongated phenotype that is particularly pronounced in the epicotyl and first internode. The long1 mutation impairs signaling from phytochrome and cryptochrome photoreceptors and interacts genetically with a mutation in LIP1, the pea ortholog of Arabidopsis thaliana COP1. Mutant long1 seedlings show a dramatic impairment in the light regulation of active GA levels and the expression of several GA biosynthetic genes, most notably the GA catabolism gene GA2ox2. The long1 mutant carries a nonsense mutation in a gene orthologous to the ASTRAY gene from Lotus japonicus, a divergent ortholog of the Arabidopsis bZIP transcription factor gene HY5. Our results show that LONG1 has a central role in mediating the effects of light on GA biosynthesis in pea and demonstrate the importance of this regulation for appropriate photomorphogenic development. By contrast, LONG1 has no effect on GA responsiveness, implying that interactions between LONG1 and GA signaling are not a significant component of the molecular framework for light–GA interactions in pea.

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Section: Shoot Phenotype Of the Long1 Mutantmentioning

confidence: 64%

Section: Long1 Mediates the Rapid Effects Of Light On Ga Economymentioning

confidence: 97%

Light Regulation of Gibberellin Biosynthesis in Pea Is Mediated through the COP1/HY5 Pathway

et al. 2009

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“…One approach that has been used to investigate the role of GAs in seed set is ectopic expression in transgenic Arabidopsis of a cDNA, isolated from Pisum sativum L. (garden pea), encoding a GA 2-oxidase. This 2-oxidase, PsGA2ox2 (also known as 2ox2), can convert the active GAs, GA 1 and GA 4 , into the irreversibly inactivated products, GA 8 and GA 34 , respectively (Lester et al 1999). In several independent 35S : 2ox2 lines seed development is abnormal and siliques contain seeds that have aborted at various stages after fertilisation (Singh et al 2002).…”

Section: Introductionmentioning

confidence: 99%

Localised and non-localised promotion of fruit development by seeds in Arabidopsis

Cox¹,

Swain²

2006

Functional Plant Biol.

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Abstract. In Arabidopsis, as in the majority of flowering plants, developing seeds promote fruit growth. One method to investigate this interaction is to use plants with reduced seed set and determine the effect on fruit growth. Plants homozygous for a transgene designed to ectopically express a gene encoding a gibberellin-deactivating enzyme exhibit reduced pollen tube elongation, suggesting that the plant hormone gibberellin is required for this process. Reduced pollen tube growth causes reduced seed set and decreased silique (fruit) size, and this genotype is used to explore the relationship between seed set and fruit elongation. A detailed analysis of seed set in the transgenic line reveals that reduced pollen tube growth decreases the probability of each ovule being fertilised. This effect becomes progressively more severe as the distance between the stigma and the ovule increases, revealing the complex biology underlying seed fertilisation. In terms of seed-promoted fruit growth, major localised and minor non-localised components that contribute to final silique length can be identified. This result demonstrates that despite the relatively small size of the fruit and associated structures, Arabidopsis can be used as a model to investigate fundamental questions in fruit physiology.

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“…By contrast, a recently characterized class of GA-catabolizing enzymes, the GA 2-oxidases, are involved in the irreversible conversion of active GAs and their precursors to inactive forms and potentially can be used to reduce the endogenous levels of active GAs. cDNAs that encode 2-oxidases were isolated recently from runner bean, Arabidopsis, pea, and rice (MacMillan et al, 1997;Lester et al, 1999;Martin et al, 1999;Thomas et al, 1999;Sakamoto et al, 2001) and shown to perform oxidation reactions at carbon 2 of various biologically active and inactive GAs in vitro. In addition, several ESTs from lotus, Medicago , maize, soybean, and tomato, and sequences from the Arabidopsis and rice genome-sequencing projects, have been identified as putative GA 2-oxidases (Elliott et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Gibberellins Are Required for Seed Development and Pollen Tube Growth in Arabidopsis

2002

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Gibberellins (GAs) are tetracyclic diterpenoids that are essential endogenous regulators of plant growth and development. GA levels within the plant are regulated by a homeostatic mechanism that includes changes in the expression of a family of GA-inactivating enzymes known as GA 2-oxidases. Ectopic expression of a pea GA 2-oxidase2 cDNA caused seed abortion in Arabidopsis, extending and confirming previous observations obtained with GA-deficient mutants of pea, suggesting that GAs have an essential role in seed development. A new physiological role for GAs in pollen tube growth in vivo also has been identified. The growth of pollen tubes carrying the 35S:2ox2 transgene was reduced relative to that of nontransgenic pollen, and this phenotype could be reversed partially by GA application in vitro or by combining with spy-5 , a mutation that increases GA response. Treatment of wild-type pollen tubes with an inhibitor of GA biosynthesis in vitro also suggested that GAs are required for normal pollen tube growth. These results extend the known physiological roles of GAs in Arabidopsis development and suggest that GAs are required for normal pollen tube growth, a physiological role for GAs that has not been established previously.

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Gibberellin 2‐oxidation and the SLN gene of Pisum sativum

Cited by 121 publications

References 29 publications

Light Regulation of Gibberellin Biosynthesis in Pea Is Mediated through the COP1/HY5 Pathway

Light Regulation of Gibberellin Biosynthesis in Pea Is Mediated through the COP1/HY5 Pathway

Localised and non-localised promotion of fruit development by seeds in Arabidopsis

Gibberellins Are Required for Seed Development and Pollen Tube Growth in Arabidopsis

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