Physiological analysis of transgenic Arabidopsis thaliana plants expressing one nitrilase isoform in sense or antisense direction

Grsic, Slobodanka; Sauerteig, Sylvia; Neuhaus, Klaus; Albrecht, Manuela; Rossiter, John T.; Ludwig‐Müller, Jutta

doi:10.1016/s0176-1617(98)80173-9

Cited by 26 publications

(23 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Alternatively, IAN is primarily involved in camalexin biosynthesis and only converted to IAA when excess IAN accumulates. The latter idea may explain why the expression of NIT1 and NIT2 is induced by exogenous IAN (Grsic et al, 1998). Another source of IAN is the turnover of indole glucosinolates (Bones and Rossiter, 2006).…”

Section: Ian and Auxinmentioning

confidence: 99%

ArabidopsisCytochrome P450 Monooxygenase 71A13 Catalyzes the Conversion of Indole-3-Acetaldoxime in Camalexin Synthesis

Goregaoker²,

et al. 2007

View full text Add to dashboard Cite

Camalexin (3-thiazol-2-yl-indole) is an indole alkaloid phytoalexin produced by Arabidopsis thaliana that is thought to be important for resistance to necrotrophic fungal pathogens, such as Alternaria brassicicola and Botrytis cinerea. It is produced from Trp, which is converted to indole acetaldoxime (IAOx) by the action of cytochrome P450 monooxygenases CYP79B2 and CYP79B3. The remaining biosynthetic steps are unknown except for the last step, which is conversion of dihydrocamalexic acid to camalexin by CYP71B15 (PAD3). This article reports characterization of CYP71A13. Plants carrying cyp71A13 mutations produce greatly reduced amounts of camalexin after infection by Pseudomonas syringae or A. brassicicola and are susceptible to A. brassicicola, as are pad3 and cyp79B2 cyp79B3 mutants. Expression levels of CYP71A13 and PAD3 are coregulated. CYP71A13 expressed in Escherichia coli converted IAOx to indole-3-acetonitrile (IAN). Expression of CYP79B2 and CYP71A13 in Nicotiana benthamiana resulted in conversion of Trp to IAN. Exogenously supplied IAN restored camalexin production in cyp71A13 mutant plants. Together, these results lead to the conclusion that CYP71A13 catalyzes the conversion of IAOx to IAN in camalexin synthesis and provide further support for the role of camalexin in resistance to A. brassicicola.

show abstract

Section: Ian and Auxinmentioning

confidence: 99%

ArabidopsisCytochrome P450 Monooxygenase 71A13 Catalyzes the Conversion of Indole-3-Acetaldoxime in Camalexin Synthesis

Goregaoker²,

et al. 2007

View full text Add to dashboard Cite

show abstract

“…IAA is an auxin and some microarrays analyses have demonstrated up-regulation of NIT1 and NIT2 in response to IAN and NaCl treatment (Grsic et al, 1998;Jiang et al, 2007;Woodward and Bartel, 2005). Furthermore, NAC transcription factor also controls salinity stress via the auxin pathway (He et al, 2005;Park et al, 2011).…”

Section: Ataf2 Is Required For Full Induction Of Nit2 In Arabidopsismentioning

confidence: 99%

ATAF2, a NAC Transcription Factor, Binds to the Promoter and Regulates NIT2 Gene Expression Involved in Auxin Biosynthesis

Huh

Lee

Kim

et al. 2012

Molecules and Cells

View full text Add to dashboard Cite

The transcription factor ATAF2, one of the plant specific NAC family genes, is known as repressor of pathogenesisrelated genes and responsive to the diverse defense-related hormones, pathogen infection, and wounding stress. Furthermore, it is important to consider that tryptophandependant IAA biosynthesis pathway can be activated by wounding and pathogen. We found that ATAF2pro::GUS reporter was induced upon indole-3-acetonitrile (IAN) treatments. And ataf2 mutant showed reduced sensitivity to IAN whereas 35S::ATAF2 plants showed hyper-sensitivity to IAN. IAN biosynthesis required nitrilase involved in the conversion of IAN to an auxin, indole-3-acetic acid (IAA). We found that the NIT2 gene was repressed in ataf2 knockout plants. Expression of both ATAF2 and NIT2 genes was induced by IAN treatment. Transgenic plants overexpressing ATAF2 showed up-regulated NIT2 expression. ATAF2 activated promoter of the NIT2 gene in Arabidopsis protoplasts. Electrophoretic mobility shift assay revealed that NIT2 promoter region from position -117 to -82 contains an ATAF2 binding site where an imperfect palindrome sequence was critical to the protein-DNA interaction. These findings indicate that ATAF2 regulates NIT2 gene expression via NIT2 promoter binding.

show abstract

Section: The Role Of Ian In Iaa Biosynthesismentioning

confidence: 99%

“…Similarly, overexpression of any of the four nitrilases in Arabidopsis did not lead to an IAA phenotype under normal conditions (Normanly et al, 1997;Grsic et al, 1998;Grsic-Rausch et al, 2000). CYP83B1 is thus the first enzyme demonstrated to regulate auxin production from tryptophan in Arabidopsis.…”

mentioning

confidence: 95%

“…Also, the observation that the isotope enrichment of IAN is lower than that for IAA when radiolabeled tryptophan is administered to either Arabidopsis roots or shoots (Normanly et al, 1993;Müller et al, 1998) indicates that IAN may not be a direct product of indole-3-acetaldoxime metabolism in IAA biosynthesis. Ectopic overexpression of the nitrilases does not give rise to an apparent IAA phenotype under normal conditions (Normanly et al, 1997;Grsic et al, 1998).In addition to indole-3-acetonitrile, indole-3-acetaldehyde derived from indole-3-acetaldoxime or indole-3-pyruvic acid has also been suggested to be a precursor of IAA biosynthesis. Labeling studies have shown that indole-3-acetaldoxime can be converted to IAA with indole-3-acetaldehyde as an intermediate in higher plants (Rajapogal and Larsen, 1972).…”

mentioning

confidence: 99%

See 1 more Smart Citation

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

et al. 2001

View full text Add to dashboard Cite

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...

show abstract

Physiological analysis of transgenic Arabidopsis thaliana plants expressing one nitrilase isoform in sense or antisense direction

Cited by 26 publications

References 24 publications

ArabidopsisCytochrome P450 Monooxygenase 71A13 Catalyzes the Conversion of Indole-3-Acetaldoxime in Camalexin Synthesis

ArabidopsisCytochrome P450 Monooxygenase 71A13 Catalyzes the Conversion of Indole-3-Acetaldoxime in Camalexin Synthesis

ATAF2, a NAC Transcription Factor, Binds to the Promoter and Regulates NIT2 Gene Expression Involved in Auxin Biosynthesis

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

Contact Info

Product

Resources

About