Synthesis of Brassinolide

McMorris, Trevor C.; Donaubauer, John R.; Silveira, Michael H.; Molinski, Tadeusz F.

doi:10.1021/bk-1991-0474.ch004

Cited by 4 publications

(2 citation statements)

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“…Seedlings were grown for 10 to 14 d in a greenhouse (25-270C) under natural lighting conditions before harvesting for the epicotyl assay. BR [2a,3a,22(R), 23(R)-tetrahydroxy-24(S)-methyl-B-homo-7-oxa-5a-cholestan-6-one] was synthesized as previously described and characterized by NMR (19 . Approximately 400,000 cpm of acid-precipitable counts of control and BR+ translation products were loaded on 4% polyacrylamide tube gels containing a 2:1 mixture of pH 5/7 and pH 3/10 ampholytes.…”

Section: Materials and Methods Plant Growth And Chemicalsmentioning

confidence: 99%

Effect of Brassinolide on Gene Expression in Elongating Soybean Epicotyls

Clouse

Zurek²,

McMorris³

et al. 1992

Plant Physiol.

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We have studied the effect of brassinolide (BR), a plant steroidal lactone, on the expression of auxin-regulated genes in soybean (Glycine max L. cv Williams 82) epicotyls. BR caused up to 4-fold increases in epicotyl length during extended assays at 10-M, in the absence of added auxin. Structurally related steroids failed to induce elongation or to alter the BR effect. Northern blot analysis, using sequences corresponding to auxin-regulated genes as probes, has shown that the molecular mechanism of BR-induced elongation is likely to differ from that of auxin-induced elongation in this system. BR does not rapidly induce members of the GH, SAUR, or ICW auxin-inducible gene families before the onset of elongation. BR enhances SAUR and GH1 transcripts after 18 h but has no effect on JCW1 or GH3 transcripts at any time examined. We have shown by two-dimensional gel analysis of in vitro translated mRNA that a submicromolar concentration of BR alters the pattern of gene expression in elongating soybean epicotyls.BR2, a plant growth-promoting steroidal lactone, is the most biologically active compound of a group of related natural products termed brassinosteroids (reviewed in ref. 13). BR elicits a broad spectrum of responses in plants including enhanced cell elongation (13) and division and differentiation (6), and a strong case recently has been made for brassinosteroids as a sixth class of endogenous plant growth regulators (25). Like auxin, BR has pronounced effects on the elongation of stem tissue. Maize mesocotyls, pea, Azuki bean, and mung bean epicotyls (9, 13, 30), bean and cucumber hypocotyls (12,14), and wheat coleoptiles (23) all respond to submicromolar concentrations of BR by elongating. It has been suggested that the effects of BR are mediated through auxin or that BR increases tissue sensitivity to endogenous auxins (13). Despite numerous physiological studies addressing BR-auxin interactions, there have been few studies reported in which molecular techniques were utilized to clarify the interaction of these growth regulators (6). '

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Section: Materials and Methods Plant Growth And Chemicalsmentioning

confidence: 99%

Effect of Brassinolide on Gene Expression in Elongating Soybean Epicotyls

Clouse

Zurek²,

McMorris³

et al. 1992

Plant Physiol.

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“…Assay protocols were as previously described for the soybean epicotyl elongation assay (Clouse et al 1992). Brassinolide (2ct,3ct22(R),23(R)-tetrahydroxy-24(S)-methyl-B-homo-7-oxa-5ct-cholestan-6-one) was synthesized and characterized by NMR as previously described (McMorris et al 1991). The naturally occurring isomer of BR, 24-epibrassinolide (EBR), was a gift of Dr. Ikekawa (Iwaki Meisei University, Iwaki, Japan) (Ikekawa and Zhao 1991).…”

Section: Plant Growth and Peduncle Elongation Assaymentioning

confidence: 99%

Physiological and molecular effects of brassinosteroids on Arabidopsis thaliana

Clouse

Hall

Langford

et al. 1993

J Plant Growth Regul

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We examined the effects of brassinosteroids on Arabidopsis thaliana (L.) Henyh. ecotype Columbia in order to develop a model system for studying gene regulation by plant steroids. Submicromolar concentrations of two brassinosteroids, brassinolide and 24-epibrassinolide, stimulated elongation of Arabidopsis peduncles and inhibited root elongation, respectively. Furthermore, brassinolide altered the abundance of specific in vitro translatable mRNAs from peduncles and whole plants of Arabidopsis. Root elongation in the auxininsensitive Arabidopsis mutant axrl was inhibited by 24-epibrassinolide but not by 2,4-D, indicating an independent mode of action for these growth regulators in this physiological response.Brassinosteroids are plant growth-promoting natural products with structural similarities to insect and animal steroid hormones (Mandava 1988). Brassinolide (BR), the first brassinosteroid to be structurally characterized (Grove et al. 1979), was originally isolated from Brassica napus pollen and was shown to induce cell elongation and proliferation at nanomolar concentrations in bean, rice, and many other plants. Subsequent work identified other brassinosteroids with similar structures from a broad range of plants including rice, maize, mustard, and wheat (Mandava 1988). The physiological effects and agricultural applications of brassinosteroids have been widely studied, and there is growing evidence that these compounds have properties characteris-

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