The<i>SUR2</i>gene of<i>Arabidopsis thaliana</i>encodes the cytochrome P450 CYP83B1, a modulator of auxin homeostasis

Barlier, Isabelle; Kowalczyk, Mariusz; Marchant, Alan; Ljung, Karin; Bhalerao, Rishikesh P.; Bennett, Malcolm J.; Sandberg, Goeran; Bellini, Catherine

doi:10.1073/pnas.260502697

Cited by 277 publications

(249 citation statements)

References 35 publications

(37 reference statements)

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“…These results are in agreement with other reports in which the modiWcation of endogenous free IAA level caused similar modiWcation of the auxin catabolites and conjugates (e.g. Barlier et al 2000). A signiWcant reduction of the auxin level due to the ectopic overexpression of APRX was observed in OE-APRX roots.…”

Section: Aprx Is Involved In Auxin Catabolismsupporting

confidence: 93%

“…The balance between auxin biosynthesis and metabolism, including conjugation, deconjugation, and catabolism, determines the level of the active hormone (Bartel 1997). In A. thaliana several genes involved in auxin homeostasis are known to contain auxin response elements in their promoters (Barlier et al 2000). Furthermore recent studies have revealed that speciWc auxin-mediated responses are controlled via a negative (auto)feedback loop (Tatematsu et al 2004).…”

Section: Aprx Is Involved In Auxin Catabolismmentioning

confidence: 99%

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An anionic class III peroxidase from zucchini may regulate hypocotyl elongation through its auxin oxidase activity

Cosio

Vuillemin

Meyer

et al. 2009

Planta

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The high number of peroxidase genes explains the description of numerous physiological functions and the fact that the in planta function of a single isoform has never been characterized yet. We analyzed in transgenic Arabidopsis thaliana the localization of a zucchini isoperoxidase (APRX), previously puriWed thanks to its pectin binding ability. We conWrmed that the protein is localized near the cell wall, mainly produced in the elongation area of the hypocotyls and respond to exogenous auxin. In addition, the ectopic overexpression of APRX induced changes in growth pattern and a signiWcant reduction of endogenous indole-3-acetic acid (IAA) level. In agreement with these observations APRX showed an elevated in vitro auxin oxidase activity. We propose that APRX participates in the negative feedback regulation of auxin level and consequently terminates the hypocotyl elongation process.

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Section: Aprx Is Involved In Auxin Catabolismsupporting

confidence: 93%

Section: Aprx Is Involved In Auxin Catabolismmentioning

confidence: 99%

An anionic class III peroxidase from zucchini may regulate hypocotyl elongation through its auxin oxidase activity

Cosio

Vuillemin

Meyer

et al. 2009

Planta

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“…This strongly suggested that rnt1-1 is an allele of sur2 , a mutant known to accumulate elevated levels of free IAA . Recently, sur2 was indeed demonstrated to be a CYP83B1 mutant (Barlier et al, 2000). As described for sur2 seedlings, rnt1-1 seedlings are characterized by increased hypocotyl length, epinastic cotyledons, exfoliation of the hypocotyl, adventitious root formation from the hypocotyl, enhanced secondary root and root hair formation, and eventually callus formation and increasing disintegration of the seedling (Table 1 and Figures 1 and 2).…”

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confidence: 79%

“…In addition, we have shown that CYP83B1 catalyzes the first committed step in indole glucosinolate biosynthesis by metabolizing indole-3-acetaldoxime to its corresponding aci-nitro compound. The recently reported identity of sur2 also as CYP83B1 (Barlier et al, 2000) explains the strong auxin phenotype of the rnt1-1 mutant, which is a knockout for CYP83B1. Increased free auxin levels were previously measured in the sur2 mutant ).…”

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confidence: 93%

CYP83B1, a Cytochrome P450 at the Metabolic Branch Point in Auxin and Indole Glucosinolate Biosynthesis in Arabidopsis

et al. 2001

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Auxins are growth regulators involved in virtually all aspects of plant development. However, little is known about how plants synthesize these essential compounds. We propose that the level of indole-3-acetic acid is regulated by the flux of indole-3-acetaldoxime through a cytochrome P450, CYP83B1, to the glucosinolate pathway. A T-DNA insertion in the CYP83B1 gene leads to plants with a phenotype that suggests severe auxin overproduction, whereas CYP83B1 overexpression leads to loss of apical dominance typical of auxin deficit. CYP83B1 N-hydroxylates indole-3-acetaldoxime to the corresponding aci -nitro compound, 1-aci -nitro-2-indolyl-ethane, with a K m of 3 M and a turnover number of 53 min Ϫ 1 . The aci -nitro compound formed reacts non-enzymatically with thiol compounds to produce an N -alkyl-thiohydroximate adduct, the committed precursor of glucosinolates. Thus, indole-3-acetaldoxime is the metabolic branch point between the primary auxin indole-3-acetic acid and indole glucosinolate biosynthesis in Arabidopsis. INTRODUCTIONApical dominance, cell expansion, vascular differentiation, lateral root and root hair formation, phototropism, and root gravitropism are among the many processes in plants controlled by auxins (Davies, 1995). The level of auxin is regulated by both de novo biosynthesis and reversible and irreversible conjugation to sugars, amino acids, and peptides as well as by degradation. Although the chemical structure of the primary auxin, indole-3-acetic acid (IAA), has been known since the 1930s (Wildman, 1997), not much is known about how plants actually synthesize this essential compound. Plants appear to be capable of synthesizing IAA by both tryptophan-dependent and tryptophan-independent pathways. Classical incorporation studies with radiolabeled compounds have not unambiguously identified the precursors or elucidated the biosynthetic pathway for IAA. (For a recent review of IAA metabolism, see Normanly and Bartel [1999].)Although a number of mutants in IAA metabolic pathways and perception have been described, the genes involved and their biochemical function and physiological relevance have not all been elucidated (reviewed in Bartel, 1997;Normanly and Bartel, 1999). For example, both the rty/sur1/hls3/alf1 (Boerjan et al., 1995;Celenza et al., 1995;King et al., 1995;Lehman et al., 1996) and sur2 mutants are known to accumulate increased levels of free auxin. Identification of the gene products affected and elucidation of the biochemical roles of these proteins should increase our limited knowledge of IAA biosynthesis and regulation.A link between indole glucosinolates and auxin has often been suggested in the literature. Glucosinolates are sulfurcontaining bioactive natural products derived from amino acids and sequestered in vacuoles of cruciferous plants (Halkier, 1999). It has recently been shown that the cytochromes CYP79B2 and CYP79B3 of Arabidopsis metabolize tryptophan to indole-3-acetaldoxime. This metabolite is often suggested to be the precursor of indole-3-acetonitrile (IAN...

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“…Mutants overproducing auxin in Arabidopsis, like sur1 and sur2 (Boerjan et al, 1995;Delarue et al, 1998) or yucca (Zhao et al, 2001) produce adventitious roots on hypocotyls of light grown seedlings. SUR1 and SUR2 genes encode a C-S-lyase protein and the cytochrome P450 Cyp83B1, both involved in the indole glucosinolate pathway (Bak et al, 2001;Barlier et al, 2000;Mikkelsen et al, 2004). YUCCA1 gene encodes a flavin monooxygenase suitable for converting tryptamine in N-hydroxyl tryptamine in vitro (Zhao et al, 2001(Zhao et al, , 2002) and belongs to a family of YUCflavin mono-oxigenases from which 4 have a role in auxin biosynthesis (Cheng et al, 2006).…”

Section: Genes Asociated With the Adventitious Root Formationmentioning

confidence: 99%

Auxin Control in the Formation of Adventitious Roots

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Bellini

2011

Not Bot Hort Agrobot Cluj

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Adventitious rooting is a complex process and a key step in the vegetative propagation of economically important woody, horticultural and agricultural species, playing an important role in the successful production of elite clones. The formation of adventitious roots is a quantitative genetic trait regulated by both environmental and endogenous factors. Among phytohormones, auxin plays an essential role in regulating roots development and it has been shown to be intimately involved in the process of adventitious rooting. Great progress has been made in elucidating the auxin-induced genes and auxin signaling pathway, especially in auxin response Aux/IAA and Auxin Response Factor gene families. Although some important aspects of adventitious and lateral rooting signaling have been revealed, the intricate signaling network remains poorly understood. This review summarizes some of the current knowledge on the physiological aspects of adventitious root formation and highlights the recent progress made in the identification of putative molecular players involved in the control of adventitious rooting. Despite much has been discovered regarding the effects and regulation of auxins on plant growth since the Darwin experiments, there is much that remains unknown.

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TheSUR2gene ofArabidopsis thalianaencodes the cytochrome P450 CYP83B1, a modulator of auxin homeostasis

Cited by 277 publications

References 35 publications

An anionic class III peroxidase from zucchini may regulate hypocotyl elongation through its auxin oxidase activity

An anionic class III peroxidase from zucchini may regulate hypocotyl elongation through its auxin oxidase activity

CYP83B1, a Cytochrome P450 at the Metabolic Branch Point in Auxin and Indole Glucosinolate Biosynthesis in Arabidopsis

Auxin Control in the Formation of Adventitious Roots

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