Acyl-conjugated metabolites of brassinosteroids in cell suspension cultures of Ornithopus sativus

Kolbe, A.; Schneider, Bernd; Porzel, Andrea; Schmidt, Jürgen; Adam, G.

doi:10.1016/0031-9422(94)00742-c

Cited by 33 publications

(18 citation statements)

References 9 publications

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“…No endogenous fatty acyl-BRs have been detected so far in Arabidopsis and only endogenous BR-esters identified from several other plant species are TE-3 β -myristate (C14∶0) and TE-3 β -laureate (C12∶0) (reviewed in [56]). Previous feeding experiments with 24-EpiBL and 24-EpiCS with either α or β orientation of the hydroxy group at position C3 also showed a stereospecific selectivity for β -configuration because substrates with α-configuration were not converted to the corresponding fatty ester when applied to cell suspension culture of Ornithopus sativus [51], [52]. These data suggest that intermediates from earlier steps in BR biosynthesis up to TE possess the configuration expected to be acylated but we did not detect acylation of TE in our in vitro assay.…”

Section: Discussionmentioning

confidence: 98%

Arabidopsis PIZZA Has the Capacity to Acylate Brassinosteroids

et al. 2012

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Brassinosteroids (BRs) affect a wide range of developmental processes in plants and compromised production or signalling of BRs causes severe growth defects. To identify new regulators of plant organ growth, we searched the Arabidopsis FOX (Full-length cDNA Over-eXpressor gene) collection for mutants with altered organ size and isolated two overexpression lines that display typical BR deficient dwarf phenotypes. The phenotype of these lines, caused by an overexpression of a putative acyltransferase gene PIZZA (PIZ), was partly rescued by supplying exogenous brassinolide (BL) and castasterone (CS), indicating that endogenous BR levels are rate-limiting for the growth of PIZ overexpression lines. Our transcript analysis further showed that PIZ overexpression leads to an elevated expression of genes involved in BR biosynthesis and a reduced expression of BR inactivating hydroxylases, a transcriptional response typical to low BR levels. Taking the advantage of relatively high endogenous BR accumulation in a mild bri1-301 background, we found that overexpression of PIZ results in moderately reduced levels of BL and CS and a strong reduction of typhasterol (TY) and 6-deoxocastasterone (6-deoxoCS), suggesting a role of PIZ in BR metabolism. We tested a set of potential substrates in vitro for heterologously expressed PIZ and confirmed its acyltransferase activity with BL, CS and TY. The PIZ gene is expressed in various tissues but as reported for other genes involved in BR metabolism, the loss-of-function mutants did not display obvious growth phenotypes under standard growth conditions. Together, our data suggest that PIZ can modify BRs by acylation and that these properties might help modulating endogenous BR levels in Arabidopsis.

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Section: Discussionmentioning

confidence: 98%

Arabidopsis PIZZA Has the Capacity to Acylate Brassinosteroids

et al. 2012

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“…TE3b-laurate was also detected in L. longiflorum (Asakawa et al, 1996). The esterified metabolites also include conjugates of 3,24-diepiCS and 3,24-diepiBL with acyl components, such as laurate, myristate, and palmitate in Ornithopus sativus (Kolbe et al, 1995). However, considering that esterification of CS and BL with laurate, myristate, and palmitate requires b-epimerization, TE could be a candidate for esterification by BIA1.…”

Section: Bia1 Is a Bahd Acyltransferase-like Protein Involved In The mentioning

confidence: 99%

“…The metabolic processes that inactivate bioactive BRs include dehydrogenation at C-3 and C-23 (Hai et al, 1996;Watanabe et al, 2000), epimerization at C-2, C-3, and C-24 (Suzuki et al, 1993;Nishikawa et al, 1995), hydroxylation at C-20, C-25, and C-26 (Voigt et al, 1993;Kolbe et al, 1996;Yokota et al, 1996), side chain cleavage at C-20/22 (Kolbe et al, 1996), and sulfonation at C-22 (Rouleau et al, 1999). In addition, active BRs are inactivated through conjugation by esterification at C-3 (Kolbe et al, 1995;Asakawa et al, 1996) and glycosylation at C-2, C-3, C-23, C-25, and C-26 (Bajguz, 2007).…”

Section: Bia1 Is a Bahd Acyltransferase-like Protein Involved In The mentioning

confidence: 99%

Genetic Evidence for the Reduction of Brassinosteroid Levels by a BAHD Acyltransferase-Like Protein in Arabidopsis

et al. 2012

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Brassinosteroids (BRs) are a group of steroidal hormones involved in plant development. Although the BR biosynthesis pathways are well characterized, the BR inactivation process, which contributes to BR homeostasis, is less understood. Here, we show that a member of the BAHD (for benzylalcohol O-acetyltransferase, anthocyanin O-hydroxycinnamoyltransferase, anthranilate N-hydroxycinnamoyl/benzoyltransferase, and deacetylvindoline 4-O-acetyltransferase) acyltransferase family may play a role in BR homeostasis in Arabidopsis (Arabidopsis thaliana). We isolated two gain-of-function mutants, brassinosteroid inactivator1-1Dominant (bia1-1D) and bia1-2D, in which a novel BAHD acyltransferase-like protein was transcriptionally activated. Both mutants exhibited dwarfism, reduced male fertility, and deetiolation in darkness, which are typical phenotypes of plants defective in BR biosynthesis. Exogenous BR treatment rescued the phenotypes of the bia1-1D mutant. Endogenous levels of BRs were reduced in the bia1-1D mutant, demonstrating that BIA1 regulates endogenous BR levels. When grown in darkness, the bia1 loss-of-function mutant showed a longer hypocotyl phenotype and was more responsive to exogenous BR treatment than the wild-type plant. BIA1 expression was predominantly observed in the root, where low levels of BRs were detected. These results indicate that the BAHD acyltransferase family member encoded by BIA1 plays a role in controlling BR levels, particularly in the root and hypocotyl in darkness. Taken together, our study provides new insights into a mechanism that maintains BR homeostasis in Arabidopsis, likely via acyl conjugation of BRs.

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“…This result is the first experimental evidence for metabolic inactivation of brassinolide (1) in plants by stereochemical alteration. However, inversion of configuration at C-3 has been already observed for 24-epibrassinolide in cell cultures of Ornithopus sativus [34].…”

Section: Brassinosteroids In Arabidopsis Thaliana and Secale Cerealementioning

confidence: 86%

Reversible Conversion In The Brassinosteroid Quartet Castasterone, Brassinolide And Their 3β-Epimers

Antonchik¹,

Svatoš

Konstantinova³

et al. 2006

Zeitschrift Für Naturforschung B

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The metabolism of deuterated brassinosteroids has been studied in excised leaves of Secale cereale, and in vitro in seedlings of Arabidopsis thaliana and cell suspension cultures of Lycopersicon esculentum. In addition to the known biosynthetic conversion of castasterone to brassinolide and epimerization to 3-epicastasterone, inversion of the 3α-configured hydroxyl group of brassinolide to a 3β -configured one in 3-epibrassinolide has been observed using liquid chromatography (HPLC) with electrospray ionization (ESI) and selected ion-monitoring mass-spectrometry (SIM-MS). Administration of deuterated 3-epicastasterone and 3-epibrassinolide to Arabidopsis and Secale seedlings resulted in the formation of castasterone and brassinolide, respectively, indicating conversion of configuration at C-3 of brassinosteroids is reversible.

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Acyl-conjugated metabolites of brassinosteroids in cell suspension cultures of Ornithopus sativus

Cited by 33 publications

References 9 publications

Arabidopsis PIZZA Has the Capacity to Acylate Brassinosteroids

Arabidopsis PIZZA Has the Capacity to Acylate Brassinosteroids

Genetic Evidence for the Reduction of Brassinosteroid Levels by a BAHD Acyltransferase-Like Protein in Arabidopsis

Reversible Conversion In The Brassinosteroid Quartet Castasterone, Brassinolide And Their 3β-Epimers

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