Occurrence and formation of indole-3-acetamide in Arabidopsis thaliana

Pollmann, Stephan; Müller, Axel; Piotrowski, Markus; Weiler, Elmar W.

doi:10.1007/s00425-002-0868-4

Cited by 88 publications

(94 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…1). This expression pattern nicely reflects the kinetic of IAA during the first two weeks of seedling development, 9 and the rapid growth of seedlings during that time. Seeds usually contain high levels of stored IAA, which facilitates initial seedling growth.…”

Section: Ami1 Expression Is Presumably Suppressed By Lec1mentioning

confidence: 56%

Expression ofAMIDASE1(AMI1) is suppressed during the first two days after germination

Hoffmann

Lehmann²,

Neu³

et al. 2010

Plant Signaling & Behavior

Self Cite

View full text Add to dashboard Cite

T he regulation of cellular auxin levels is a critical factor in determining plant growth and architecture, as indole-3-acetic acid (IAA) gradients along the plant axis and local IAA maxima are known to initiate numerous plant growth responses. The regulation of auxin homeostasis is mediated in part by transport, conjugation and deconjugation, as well as by de novo biosynthesis. However, the pathways of IAA biosynthesis are yet not entirely characterized at the molecular and biochemical level. It is suggested that several biosynthetic routes for the formation of IAA have evolved. One such pathway proceeds via the intermediate indole-3-acetamide (IAM), which is converted into IAA by the activity of specific IAM hydrolases, such as Arabidopsis AMIDASE1 (AMI1). In this article we present evidence to support the argument that AMI1-dependent IAA synthesis is likely not to be used during the first two days of seedling development.Auxins are versatile plant hormones that play diverse roles in regulating many aspects of plant growth and development. 1 To enable auxins to develop their activity, a tight spatiotemporal control of cellular indole-3-acetic acid (IAA) contents is absolutely necessary since it is well-documented that auxin action is dose dependent, and that high IAA levels can have inhibitory effects on plant growth. 2 To achieve this goal, plants have evolved a set of different mechanisms to control cellular hormone levels. On the one hand, plants possess several pathways

show abstract

Section: Ami1 Expression Is Presumably Suppressed By Lec1mentioning

confidence: 56%

Expression ofAMIDASE1(AMI1) is suppressed during the first two days after germination

Hoffmann

Lehmann²,

Neu³

et al. 2010

Plant Signaling & Behavior

Self Cite

View full text Add to dashboard Cite

show abstract

“…Arabidopsis nitrilases (NIT1, NIT2, and NIT3) can convert IAN to IAA and IAM in vitro (25). Since our results indicated that IAN is mainly produced from IAOx, we hypothesized that IAM is a possible intermediate in the pathway converting IAOx to IAA (Fig.…”

Section: Ian Ig and CL Are Each Produced Independently From Iaox Inmentioning

confidence: 77%

Biochemical analyses of indole-3-acetaldoxime-dependent auxin biosynthesis in Arabidopsis

Sugawara

Hishiyama

Jikumaru

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

290

345

View full text Add to dashboard Cite

Auxins are hormones that regulate many aspects of plant growth and development. The main plant auxin is indole-3-acetic acid (IAA), whose biosynthetic pathway is not fully understood. Indole-3-acetaldoxime (IAOx) has been proposed to be a key intermediate in the synthesis of IAA and several other indolic compounds. Genetic studies of IAA biosynthesis in Arabidopsis have suggested that 2 distinct pathways involving the CYP79B or YUCCA (YUC) genes may contribute to IAOx synthesis and that several pathways are also involved in the conversion of IAOx to IAA. Here we report the biochemical dissection of IAOx biosynthesis and metabolism in plants by analyzing IAA biosynthesis intermediates. We demonstrated that the majority of IAOx is produced by CYP79B genes in Arabidopsis because IAOx production was abolished in CYP79B-deficient mutants. IAOx was not detected from rice, maize, and tobacco, which do not have apparent CYP79B orthologues. IAOx levels were not significantly altered in the yuc1 yuc2 yuc4 yuc6 quadruple mutants, suggesting that the YUC gene family probably does not contribute to IAOx synthesis. We determined the pathway for conversion of IAOx to IAA by identifying 2 likely intermediates, indole-3-acetamide (IAM) and indole-3-acetonitrile (IAN), in Arabidopsis. When 13 C6-labeled IAOx was fed to CYP79B-deficient mutants, 13 C 6 atoms were efficiently incorporated to IAM, IAN, and IAA. This biochemical evidence indicates that IAOx-dependent IAA biosynthesis, which involves IAM and IAN as intermediates, is not a common but a species-specific pathway in plants; thus IAA biosynthesis may differ among plant species.indole-3-acetic acid ͉ plant hormone

show abstract

“…Arabidopsis nitrilases (NIT1, NIT2, and NIT3) convert IAN to IAA and indole-3-acetamide (IAM) (Pollmann et al, 2002). 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).…”

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

Occurrence and formation of indole-3-acetamide in Arabidopsis thaliana

Cited by 88 publications

References 27 publications

Expression ofAMIDASE1(AMI1) is suppressed during the first two days after germination

Expression ofAMIDASE1(AMI1) is suppressed during the first two days after germination

Biochemical analyses of indole-3-acetaldoxime-dependent auxin biosynthesis in Arabidopsis

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

Contact Info

Product

Resources

About