Document Detail

Flavonoids induced in cells undergoing nodule organogenesis in white clover are regulators of auxin breakdown by peroxidase.
MedLine Citation:
PMID:  11326048     Owner:  NLM     Status:  MEDLINE    
It was tested whether flavonoids that specifically accumulate in cells undergoing early nodule organogenesis could affect auxin turnover by a peroxidase to explain local changes in auxin distribution that occur during nodule formation in white clover (Trifolium repens cv. Haifa). A fluorometric assay was developed to determine the kinetics of indoleacetic acid (IAA) breakdown rates by a horseradish peroxidase in vitro. Three flavonoid compounds, which had previously been localized and identified, were purified from root tissue and their tissue concentrations estimated. A derivative of 7,4'-dihydroxyflavone (DHF), as well as free DHF, strongly inhibited auxin breakdown by peroxidase at concentrations estimated in the root tissue. Formononetin, an isoflavonoid accumulating in nodule primordia, accelerated auxin breakdown by peroxidase at concentrations estimated to be present in the roots. These results suggest that local changes in flavonoid accumulation could regulate local auxin levels during nodule organogenesis. The results are consistent with previous observations on the localization of auxin during nodule organogenesis. A model for the interaction of flavonoids with peroxidases is proposed to explain changes auxin during nodule development. A similar mechanism could be involved in lateral root and root gall formation.
U Mathesius
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of experimental botany     Volume:  52     ISSN:  0022-0957     ISO Abbreviation:  J. Exp. Bot.     Publication Date:  2001 Mar 
Date Detail:
Created Date:  2001-04-30     Completed Date:  2003-06-13     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9882906     Medline TA:  J Exp Bot     Country:  England    
Other Details:
Languages:  eng     Pagination:  419-26     Citation Subset:  IM    
Genomic Interactions Group, Research School of Biological Sciences, Australian National University, GPO Box 475, Canberra, ACT 2601, Australia.
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MeSH Terms
Flavonoids / analysis,  chemistry,  metabolism*,  pharmacology
Indoleacetic Acids / metabolism*
Peroxidase / metabolism*
Plant Roots / chemistry,  cytology,  growth & development*,  metabolism*
Time Factors
Trifolium / metabolism*
Reg. No./Substance:
0/Flavonoids; 0/Indoleacetic Acids; EC

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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