Reversible Conversion between Teasterone and Its Ester Conjugates in Lily Cell Cultures

Soeno, Kazuo; Asakawa, Seiichi; Natsume, Masahiro; Abé, Hiroshi

doi:10.1584/jpestics.25.117

Cited by 17 publications

(15 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Notably BL levels have not been measured for many BR mutants due to its very low abundance, thus it is difficult to assess how general these apparent discrepancies are. BRs are thought to act locally within the tissue [61] and we suspect that PIZ overexpression may cause stronger down-regulation of BRs only in a subset of cells where BRs primarily function. Such local changes might be masked in our bulk analysis.…”

Section: Discussionmentioning

confidence: 99%

Arabidopsis PIZZA Has the Capacity to Acylate Brassinosteroids

et al. 2012

View full text Add to dashboard Cite

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.

show abstract

Section: Discussionmentioning

confidence: 99%

Arabidopsis PIZZA Has the Capacity to Acylate Brassinosteroids

et al. 2012

View full text Add to dashboard Cite

show abstract

“…For example, 3,24‐diepiCS and 3,24‐diepiBL were found to be conjugated to 3‐laurate, 3‐myristate or 3‐palmitate ester in serradella cells ( Ornithopus sativus ) (Kolbe et al ., , ). TE and its derivatives may be conjugated to 3‐laurate and 3‐myristate, creating several acyl metabolites in lily ( Lilium longiflorum ) cell cultures (Abe et al ., ; Asakawa et al ., , ; Kolbe et al ., ; Soeno et al ., ,b). These acyl BRs are easily converted to free TE, CS and BL intermediates by hydrolysis.…”

Section: Discussionmentioning

confidence: 99%

BAT1, a putative acyltransferase, modulates brassinosteroid levels in Arabidopsis

et al. 2012

View full text Add to dashboard Cite

SUMMARYBrassinosteroids (BRs) are essential for various aspects of plant development. Cellular BR homeostasis is critical for proper growth and development of plants; however, its regulatory mechanism remains largely unknown. BAT1 (BR-related acyltransferase 1), a gene encoding a putative acyltransferase, was found to be involved in vascular bundle development in a full-length cDNA over-expressor (FOX) screen. Over-expression of BAT1 resulted in typical BR-deficient phenotypes, which were rescued by exogenously applied castasterone and brassinolide. Analyses of BR profiles demonstrated that BAT1 alters levels of several brassinolide biosynthetic intermediates, including 6-deoxotyphasterol, typhasterol and 6-deoxocastasterone. BAT1 is mainly localized in the endoplasmic reticulum. BAT1 is highly expressed in young tissues and vascular bundles, and its expression is induced by auxin. These data suggest that BAT1 is involved in BR homeostasis, probably by conversion of brassinolide intermediates into acylated BR conjugates.

show abstract

“…Conjugated BRs, such as glycosylated or acylated compounds that are well known from several species (Fujioka and Yokota, 2003;Bajguz, 2007), may serve as reversibly inactivated storage forms, which can be mobilized enzymatically when hormone synthesis and accumulation are required. Such a reversible reaction is C-3 myristylation of teasterone that was described in lily (Lilium longiflorum), and was suggested to support BL synthesis during pollen development (Asakawa et al, 1996;Soeno et al, 2000). Conjugative reactions, rather than catabolic breakdown, can be responsible for the rapid decrease of the total BR content in fully developed pea seeds (Nomura et al, 2007).…”

Section: Discussionmentioning

confidence: 97%

Regulation of brassinosteroid metabolism

Hategan

Godza

Szekeres

2010

Brassinosteroids: A Class of Plant Hormone

View full text Add to dashboard Cite

Abstract:Brassinosteroids (BRs) participate in the regulation of important physiological processes, such as germination, photomorphogenesis, elongation, and the development of reproductive organs. Unlike other phytohormones, BRs are not subject to active transport within the plant, therefore, their levels are determined by the balance between local biosynthetic and inactivation reactions. BR accumulation shows good correlation with the induction of biosynthetic genes, which are stringently regulated, primarily at the transcriptional level. These genes function under developmental, organ-specific and diurnal control, and respond to homeostatic feedback adjustment. Excess amounts of bioactive BRs are removed by reversible or irreversible inactivation mechanisms. The regulation of BR-inactivating genes is also fairly complex and often opposite to those of the biosynthetic functions. Though many details are yet to be clarified, the known regulatory mechanisms of BR metabolism reveal a finely orchestrated system capable of ensuring optimal BR supply from germination to seed production.

show abstract

Reversible Conversion between Teasterone and Its Ester Conjugates in Lily Cell Cultures

Cited by 17 publications

References 2 publications

Arabidopsis PIZZA Has the Capacity to Acylate Brassinosteroids

Arabidopsis PIZZA Has the Capacity to Acylate Brassinosteroids

BAT1, a putative acyltransferase, modulates brassinosteroid levels in Arabidopsis

Regulation of brassinosteroid metabolism

Contact Info

Product

Resources

About