Inconsistency Between Growth and Endogenous Levels of Gibberellins, Brassinosteroids, and Sterols in Pisum Sativum Treated with Uniconazole Antipodes

Yokota, T.; Nakamura, Yasushi; Takahashi, Nobuta; Nonaka, Michiyasu; Sekimoto, Hitoshi; Oshio, Hiromichi; Takatsuto, Suguru

doi:10.1007/978-1-4612-3002-1_33

Cited by 28 publications

(21 citation statements)

References 17 publications

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“…A similar trend is observed in pea seedlings. but the relationship is not as close due to the use of racemic mixtures of uniconazole (Yokota et al, 1991).…”

Section: Mode Of Actionmentioning

confidence: 99%

“…The most potent of the plant growth regulating (GA-inhibiting) compounds in this group is uniconazole, followed by paclobutrazol ( Figure 5) and these have been extensively studied for their effects in various plant species since around 1980 (Davis and Curry, 1991). Yokota et al (1991) report that in pea cv. Holland there was a significant reduction in the levels of sterols and brassinosteroids in leaves treated with R-uniconazole than there was with S-uniconazole, which caused a greater reduction in height and GA levels.…”

Section: Triazolesmentioning

confidence: 99%

See 1 more Smart Citation

Relationship between gibberellins, height, and stress tolerance in barley (Hordeum vulgare L.) seedlings

Sarkar¹,

Perras²,

Falk

et al. 2004

Plant Growth Regulation

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“…A similar trend is observed in pea seedlings. but the relationship is not as close due to the use of racemic mixtures of uniconazole (Yokota et al, 1991).…”

Section: Mode Of Actionmentioning

confidence: 99%

Section: Triazolesmentioning

confidence: 99%

Relationship between gibberellins, height, and stress tolerance in barley (Hordeum vulgare L.) seedlings

Sarkar¹,

Perras²,

Falk

et al. 2004

Plant Growth Regulation

View full text Add to dashboard Cite

“…2B). The K d for brassinazole was 1.05 ϫ 10 Ϫ6 M. Uniconazole is also a triazole-type inhibitor mainly targeting a P450 involved in an early step of gibberellin biosynthesis and inhibits BR biosynthesis at a higher concentration than brassinazole (17). The dissociation constant for uniconazole (6.9 ϫ 10 Ϫ6 M)…”

Section: Quantitative Analysis Of Brs In Brassinazole-treatedmentioning

confidence: 99%

Selective Interaction of Triazole Derivatives with DWF4, a Cytochrome P450 Monooxygenase of the Brassinosteroid Biosynthetic Pathway, Correlates with Brassinosteroid Deficiency in Planta

Asami¹,

Mizutani²,

Fujioka³

et al. 2001

Journal of Biological Chemistry

156

112

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Brassinazole, a synthetic chemical developed in our laboratory, is a triazole-type brassinosteroid biosynthesis inhibitor that induces dwarfism in various plant species. The target sites of brassinazole were investigated by chemical analyses of endogenous brassinosteroids (BRs) in brassinazole-treated Catharanthus roseus cells. The levels of castasterone and brassinolide in brassinazole-treated plant cells were less than 6% of the levels in untreated cells. In contrast, campestanol and 6-oxocampestanol levels were increased, and levels of BR intermediates with hydroxy groups on the side chains were reduced, suggesting that brassinazole treatment reduced BR levels by inhibiting the hydroxylation of the C-22 position. DWF4, which is an Arabidopsis thaliana cytochrome P450 isolated as a putative steroid 22-hydroxylase, was expressed in Escherichia coli, and the binding affinity of brassinazole and its derivatives to the recombinant DWF4 were analyzed. Among several triazole derivatives, brassinazole had both the highest binding affinity to DWF4 and the highest growth inhibitory activity. The binding affinity and the activity for inhibiting hypocotyl growth were well correlated among the derivatives. In brassinazole-treated A. thaliana, the CPD gene involved in BR biosynthesis was induced within 3 h, most likely because of feedback activation caused by the reduced levels of active BRs. These results indicate that brassinazole inhibits the hydroxylation of the C-22 position of the side chain in BRs by direct binding to DWF4 and that DWF4 catalyzes this hydroxylation reaction.

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“…KM-01 is the first reported selective BR inhibitor, but appears to be of limited use for probing the role of BRs in plants due to its very low activity when applied alone (Kim et al, 1995). Other than KM-01, there have been no BR inhibitors, but Yokota et al (1991) observed a slight reduction in the concentration of endogenous castasterone when plants were treated with uniconazole, and Iwasaki and Shibaoka (1991) reported that this compound inhibited brassinolide-induced tracheary element differentiation. These observations imply that brassinolide biosynthesis is also affected, since uniconazole is known to block GA biosynthesis.…”

mentioning

confidence: 99%

Characterization of Brassinazole, a Triazole-Type Brassinosteroid Biosynthesis Inhibitor

et al. 2000

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Screening for brassinosteroid (BR) biosynthesis inhibitors was performed to find chemicals that induce dwarfism in Arabidopsis, mutants that resembled BR biosynthesis mutants that can be rescued by BR. Through this screening experiment, the compound brassinazole was selected as the most potent chemical. In dark-grown Arabidopsis, brassinazoleinduced morphological changes were nearly restored to those of wild type by treatment with brassinolide. The structure of brassinazole is similar to pacrobutrazol, a gibberellin biosynthesis inhibitor. However, in assays with cress (Lepidium sativum) plants, brassinazole-treated plants did not show recovery after the addition of gibberellin but showed good recovery after the addition of brassinolide. These data demonstrate that brassinazole is a specific BR biosynthesis inhibitor. Brassinazole-treated cress also showed dwarfism, with altered leaf morphology, including the downward curling and dark green color typical of Arabidopsis BR-deficient mutants, and this dwarfism was reversed by the application of 10 nm brassinolide. This result suggests that BRs are essential for plant growth, and that brassinazole can be used to clarify the function of BRs in plants as a complement to BR-deficient mutants. The brassinazole action site was also investigated by feeding BR biosynthesis intermediates to cress grown in the light.

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Inconsistency Between Growth and Endogenous Levels of Gibberellins, Brassinosteroids, and Sterols in Pisum Sativum Treated with Uniconazole Antipodes

Cited by 28 publications

References 17 publications

Relationship between gibberellins, height, and stress tolerance in barley (Hordeum vulgare L.) seedlings

Relationship between gibberellins, height, and stress tolerance in barley (Hordeum vulgare L.) seedlings

Selective Interaction of Triazole Derivatives with DWF4, a Cytochrome P450 Monooxygenase of the Brassinosteroid Biosynthetic Pathway, Correlates with Brassinosteroid Deficiency in Planta

Characterization of Brassinazole, a Triazole-Type Brassinosteroid Biosynthesis Inhibitor

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