The maize Dwarf3 gene encodes a cytochrome P450-mediated early step in Gibberellin biosynthesis.

Winkler, Rodney G.; Helentjaris, Tim

doi:10.1105/tpc.7.8.1307

Cited by 209 publications

(112 citation statements)

References 42 publications

Supporting

Mentioning

109

Contrasting

Order By: Relevance

“…The CBB3 protein might therefore act as a catalyst for a specific hydroxylation reaction in the biosynthesis of brassinosteroids. The recently isolated maize DWARF3 gene, coding for a cytochrome P450 enzyme involved in a hydroxylation step in gibberellin biosynthesis, provides an example of this type of activity (Winkler and Helentjaris, 1995). The data presented here, however, exclude an involvement of the CBB3 protein in the gibberellin biosynthetic pathway.…”

Section: Discussioncontrasting

confidence: 37%

Genetic evidence for an essential role of brassinosteroids in plant development

et al. 1996

View full text Add to dashboard Cite

SummaryBrassinosteroids which show high structural similarity to animal steroid hormones elicit a variety of growth responses when exogeneously applied to plant tissues. Thus far however, the function of endogeneous brassinosteroids in higher plants has been unclear. This paper describes three extremely dwarfed Arabidopsis thaliana mutants, cbbl (dwfl-6), cbb2and cbb3, which are impared in cell elongation controlled by brassinosteroids. While cbbl (dwfl-6) and cbb3 can be phenotypically normalized to wild-type by feeding with brassinosteroids indicating deficiencies of brassinosteroid biosynthesis, cbb2 is brassinosteroid-insensitive and defines a function required for further metabolic conversion necessary for biological activity or for perception/signal transduction of these growth-regulating plant steroid hormones. Expression of the meri5 and TCH4 genes is low in all three cbb mutants and can be restored to wild-type levels by brassinosteroid treatment in the cbbl (dwfl-6) and cbb3 mutants but are unaffected in the cbb2 mutant. These data indicate that brassinosteroids are essential for proper plant development and play an important role in the control of cell elongation.

show abstract

Section: Discussioncontrasting

confidence: 37%

Genetic evidence for an essential role of brassinosteroids in plant development

et al. 1996

View full text Add to dashboard Cite

show abstract

“…AtBR6ox and its homologs form a family with CPD and DWF4, BR-related P450 genes, in a phylogenic tree. The only exception is the maize (Zea mays) Dwarf3 gene that was reported to be involved in gibberellin biosynthesis (Winkler and Helentjaris 1995). The present work demonstrated that AtBR6ox and tomato Dwarf are involved in C-6 oxidation, and hence the corresponding proteins were designated BR-6-oxidases.…”

Section: Discussionmentioning

confidence: 77%

Brassinosteroid-6-Oxidases from Arabidopsis and Tomato Catalyze Multiple C-6 Oxidations in Brassinosteroid Biosynthesis

et al. 2001

View full text Add to dashboard Cite

Brassinosteroids (BRs) are steroidal plant hormones that are essential for growth and development. It has been proposed that BRs are synthesized via two parallel pathways, the early and late C-6 oxidation pathways according to the C-6 oxidation status. The tomato (Lycopersicon esculentum) Dwarf gene encodes a cytochrome P450 that has been shown to catalyze the C-6 oxidation of 6-deoxocastasterone to castasterone. We isolated an Arabidopsis ortholog (AtBR6ox gene) of the tomato Dwarf gene. The encoded polypeptide has characteristics of P450s and is classified into the CYP85 family. The AtBR6ox and tomato Dwarf gene were expressed in yeast and the ability of the transformed yeast cells to metabolize 6-deoxo-BRs was tested. Metabolites were analyzed by gas chromatography-mass spectrometry. Both enzymes catalyze multiple steps in BR biosynthesis: 6-deoxoteasterone to teasterone, 3-dehydro-6-deoxoteasterone to 3-dehydroteasterone, 6-deoxotyphasterol to typhasterol, and 6-deoxocastasterone to castasterone. Our results indicate that the AtBR6ox gene and the tomato Dwarf gene encode steroid-6-oxidases and that these enzymes have a broad substrate specificity. This suggests that the BR biosynthetic pathway consists of a metabolic grid rather than two separate parallel pathways.

show abstract

“…2). An amino acid alignment of two CYP proteins involved in brassinosteroid biosynthesis (22␣-hydroxylase DWF4/CYP90B1 [Choe et al, 1998]; 23␣-hydroxylase CPD/CYP90A1 [Szekeres et al, 1996]) and other CYP proteins that are involved in gibberellin biosynthesis and dwarfism (DWF3/ CYP88A1 [Winkler and Helentjaris, 1995]; ROTUN-DIFOLIA/CYP90C1 [Kim et al, 1998]; and DWARF/ CYP85 [Bishop et al, 1996]) with CYP87A3 revealed highly conserved domains in these proteins in addition to the C-terminal heme-binding domain. All of these proteins exhibit a central region with steroid substrate-binding and oxygen-binding domains (Fig.…”

Section: Cyp87a3 Is Coding For a Protein That Belongs To The Cyp Supementioning

confidence: 99%

Auxin Responsiveness of a Novel Cytochrome P450 in Rice Coleoptiles

et al. 2003

View full text Add to dashboard Cite

An early auxin-induced gene was isolated from rice (Oryza sativa L. subsp. japonica cv Nihonmasari) coleoptiles by a fluorescent-labeled differential display screen. The full-length gene contains conserved domains characteristic for the cytochrome P450 superfamily. This gene, designated as CYP87A3, was weakly expressed in dark-grown coleoptiles but was up-regulated rapidly and transiently when coleoptile segments were incubated in 5 m indole-3-acetic acid. This induction by auxin could not be suppressed by cycloheximide. Depletion of segments from endogenous auxin reduced the amount of CYP87A3 transcripts. The CYP87A3 transcript level was rapidly, although transiently, up-regulated in response to light as well. The observed pattern of gene regulation might indicate a role in the suppression of auxin-induced coleoptile growth. The role of CYP87A3 is discussed with respect to auxin signaling in the regulation of coleoptile growth.Coleoptiles represent a classical model system to study the control of growth-related signaling, because they grow exclusively by cell elongation (Wada, 1961) and respond to environmental signals. The plant hormone auxin plays a central role in the control of coleoptile elongation. As a matter of fact, auxin was discovered as a powerful growth substance that is produced mainly in the coleoptile tip, migrates basipetally, and is crucial for the signaldependent regulation of growth (Went, 1928).Although the importance of basipetal auxin transport has been confirmed by a wealth of data collected over several decades (for review, see Masuda et al., 1998), the role of auxin in the signal-dependent growth response appears to be complex. As shown by recent data, auxin distribution depends on several intrinsic activities, mainly synthesis, conjugation/deconjugation, and catabolism (for review, see Normanly, 1997). Moreover, changes in auxin transport between neighboring tissues and/or local concentrations can influence growth. For instance, a correlation between growth inhibition and a decrease in the level of extractable indole-3-acetic acid (IAA) could be demonstrated in the epidermis of irradiated pea (Pisum sativum) seedlings (Behringer and Davies, 1992). In addition, sensitivity/responsiveness of the target tissue to auxin have to be considered (Trewavas, 1981). Because of this complexity, the events underlying signaling mediating auxin-triggered cell elongation are still far from being understood.Growing evidence has appeared concerning regulation of auxin action at the level of gene expression (for example, expressional control of primary auxinresponsive genes, such as members of GH3 or Aux/ IAA family; see Leyser, 2002; Hagen and Guilfoyle, 2002; Nakazawa et al., 2001). From the expression pattern of such genes, their role in signaling as well as their putative function have been inferred. We therefore ventured to isolate auxin-regulated gene(s) related to auxin-induced elongation. Using fluorescent differential display (FDD; Kuno et al., 2000), we screened for a subset of auxin-induced...

show abstract

The maize Dwarf3 gene encodes a cytochrome P450-mediated early step in Gibberellin biosynthesis.

Cited by 209 publications

References 42 publications

Genetic evidence for an essential role of brassinosteroids in plant development

Genetic evidence for an essential role of brassinosteroids in plant development

Brassinosteroid-6-Oxidases from Arabidopsis and Tomato Catalyze Multiple C-6 Oxidations in Brassinosteroid Biosynthesis

Auxin Responsiveness of a Novel Cytochrome P450 in Rice Coleoptiles

Contact Info

Product

Resources

About