Blockage of Brassinosteroid Biosynthesis and Sensitivity Causes Dwarfism in Garden Pea

Nomura, T.; Nakayama, Masayoshi; Reid, James B.; Takeuchi, Yoshinori; Yokota, Takao

doi:10.1104/pp.113.1.31

Cited by 193 publications

(106 citation statements)

References 26 publications

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“…Such evidence is only present for a few developmental processes including stem elongation (e.g. Nomura et al 1997), xylem differentiation (Yamamoto et al 2001) and fruit development (Symons et al 2006), and then only in a select number of angiosperm species. Such physiological evidence is lacking from other plant groups.…”

Section: Occurrence Biosynthesis and Biological Activitymentioning

confidence: 99%

Evolution of growth-promoting plant hormones

Ross

Reid

2010

Functional Plant Biol.

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Abstract. The plant growth hormones auxin, gibberellins (GAs) and brassinosteroids (BRs) are major determinants of plant growth and development. Recently, key signalling components for these hormones have been identified in vascular plants and, at least for the GAs and BRs, biosynthetic pathways have been clarified. The genome sequencing of a range of species, including a few non-flowering plants, has allowed insight into the evolution of the hormone systems. It appears that the moss Physcomitrella patens can respond to auxin and contains key elements of the auxin signalling pathway, although there is some doubt as to whether it shows a fully developed rapid auxin response. On the other hand, P. patens does not show a GA response, even though it contains genes for components of GA signalling. The GA response system appears to be more advanced in the lycophyte Selaginella moellendorffii than in P. patens. Signalling systems for BRs probably arose after the evolutionary divergence of the mosses and vascular plants, although detailed information is limited. Certainly, the processes affected by the growth hormones (e.g. GAs) can differ in the different plant groups, and there is evidence that with the evolution of the angiosperms, the hormone systems have become more complex at the gene level. The intermediate nature of mosses in terms of overall hormone biology allows us to speculate about the possible relationship between the evolution of plant growth hormones and the evolution of terrestrial vascular plants in general.

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Section: Occurrence Biosynthesis and Biological Activitymentioning

confidence: 99%

Evolution of growth-promoting plant hormones

Ross

Reid

2010

Functional Plant Biol.

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“…Several studies have concluded that the BR promotion of cell elongation in soybean and tomato and the BR inhibition of root elongation in Arabidopsis are likely not mediated by auxin signaling pathways (Clouse et al, 1992(Clouse et al, , 1993Zurek et al, 1994). On the other hand, McKay et al (1994) reported that IAA levels are reduced in the youngest internodes but not in the apical portion of the pea BR-insensitive mutant lka and the BR-deficient mutant lkb (Nomura et al, 1997) when compared with the WT. Therefore, the possibility cannot be excluded that the endogenous BRs increases the endogenous IAA content.…”

mentioning

confidence: 99%

Brassinolide InducesIAA5, IAA19, and DR5, a Synthetic Auxin Response Element in Arabidopsis, Implying a Cross Talk Point of Brassinosteroid and Auxin Signaling

et al. 2003

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Despite numerous physiological studies addressing the interactions between brassinosteroids (BRs) and auxins, little is known about the underlying molecular mechanisms. We studied the expression of IAA5 and IAA19 in response to treatment with indole acetic acid (IAA) or brassinolide (BL), the most active BR. Exogenous IAA induced these genes quickly and transiently, whereas exogenous BL induced them gradually and continuously. We also found that a fusion of DR5, a synthetic auxin response element, with the GUS (␤-glucuronidase) gene was induced with similar kinetics to those of the IAA5 and IAA19 genes in response to both IAA and BL treatment of transgenic plants. These results suggest that the IAA genes are induced by BL, at least in part, via the activation of the auxin response element. Endogenous IAA levels per gram fresh weight did not increase when seedlings of Arabidopsis wild type (WT) or the BR-deficient mutant det2 were treated with BL. Furthermore, the levels of IAA transcripts were lower in the det2 mutant than in the WT, even though endogenous IAA levels per gram fresh weight were higher in the det2 mutant than in the WT. In conclusion, the lack of evidence for auxin-mediated activation of early auxin-inducible genes in response to BL suggests that the BR and auxin signaling pathways independently activate the transcriptional system of the IAA and DR5-GUS genes.Exogenous application of brassinosteroids (BRs) to plants at nanomolar to micromolar concentrations produces a wide spectrum of physiological effects. These include promotion of cell elongation and division, enhancement of tracheary element differentiation, delaying of abscission, enhancement of gravityinduced bending, promotion of ethylene biosynthesis, and enhancement of stress resistance, as reviewed by Clouse and Sasse (1998) andSasse (1999). A number of BR-deficient mutants have been identified in Arabidopsis, pea (Pisum sativum), and tomato (Lycopersicon esculentum; for review, see Clouse and Feldmann, 1999;Clouse, 2002; Fujioka and Yokota, 2003). These mutants exhibit dwarfism when grown in either light or dark conditions. Many of these mutants also have dark-green leaves, reduced fertility, a prolonged life span, and abnormal skotomorphogenesis. BR-insensitive mutants have been identified in Arabidopsis, pea, tomato, and rice (Oryza sativa; for review, see Clouse and Feldmann, 1999;Clouse, 2002; Fujioka and Yokota, 2003). The molecular mechanisms of BR action, however, remain unclear.It has been suggested that the actions of BRs are related to auxin action (Mandava, 1988;Sasse, 1999). Synergistic interactions between BRs and auxins occur in elongating tissues and cells in dicots (Yopp et al., 1981;Katsumi, 1985;Sala and Sala, 1985) and in monocots (Yopp et al., 1981). Such synergism is also found in the bending responses of dicots (Yopp et al., 1981; Cohen and Meudt, 1983;Meudt, 1987) and monocots (Takeno and Pharis, 1982; Fujioka et al., 1998). Several authors have proposed that BRinduced effects might be mediated via auxin, wi...

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“…Studies of the biosynthetic pathway of BRs using cultured cells of Catharanthus roseus have revealed that BL is biosynthesized from campesterol by two parallel branched pathways (Fujioka and Sakurai, 1997b;Sakurai and Fujioka, 1997). Moreover, a number of BR-deficient dwarf mutants of Arabidopsis, pea, and tomato have been identified (det2 [Li et al, 1996Fujioka et al, 1997]; dwf1/dim [Takahashi et al, 1995;Klahre et al, 1998;Choe et al, 1999a]; cpd [Szekeres et al, 1996]; dwf4 [Azpiroz et al, 1998;Choe et al, 1998]; dwf7 [Choe et al, 1999b]; lkb [Nomura et al, 1997]; tomato dwarf [Bishop et al, 1996[Bishop et al, , 1999). These mutants exhibit intriguing phenotypes such as dwarfism and de-etiolation, and the findings of BR mutants led to wide acceptance of essential roles for BRs in plant growth and development (Yokota, 1997;Altmann, 1998;Clouse and Feldmann, 1999).…”

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confidence: 99%

Arabidopsis det2 Is Defective in the Conversion of (24R)-24-Methylcholest-4-En-3-One to (24R)-24-Methyl-5α-Cholestan-3-One in Brassinosteroid Biosynthesis1

et al. 1999

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Previously, we have shown that the Arabidopsis det2 (deetiolated2) mutant is defective in the biosynthesis of brassinosteroids (BR) and that DET2 (a steroid 5␣-reductase) acts early in the proposed BR biosynthetic pathway. In this paper we present further biochemical characterization of det2. We have undertaken metabolic experiments with 2 H-labeled substrates of intermediates involved in the formation of campestanol from campesterol, and quantitative analysis of intermediates in Arabidopsis wild type and det2. The results of these studies indicate the early operating steps of BR biosynthesis as: campesterol 3 4-en-3␤-ol 3 4-en-3-one 3 3-one 3 campestanol in Arabidopsis, with det2 deficient in the conversion of 4-en-3-one to 3-one. We have also detected these intermediates in the formation of campestanol from campesterol and their metabolic conversions using cultured cells of Catharanthus roseus. These studies confirmed the biosynthetic sequence of events from campesterol to campestanol as was found in Arabidopsis. As such, the originally proposed biosynthetic pathway should be modified.

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Blockage of Brassinosteroid Biosynthesis and Sensitivity Causes Dwarfism in Garden Pea

Cited by 193 publications

References 26 publications

Evolution of growth-promoting plant hormones

Evolution of growth-promoting plant hormones

Brassinolide InducesIAA5, IAA19, and DR5, a Synthetic Auxin Response Element in Arabidopsis, Implying a Cross Talk Point of Brassinosteroid and Auxin Signaling

Arabidopsis det2 Is Defective in the Conversion of (24R)-24-Methylcholest-4-En-3-One to (24R)-24-Methyl-5α-Cholestan-3-One in Brassinosteroid Biosynthesis1

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