Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2010-6-29
pubmed:abstractText
Flavonoid signals from alfalfa (Medicago sativa L.) induce transcription of nodulation (nod) genes in Rhizobium meliloti. Previous investigations identified the flavone luteolin as an active inducer in alfalfa seed extracts, but the nature of nod inducers released from roots has not been reported. Root exudate from 3-day-old alfalfa seedlings was purified and then assayed for biological activity with a nodABC-lacZ fusion in R. meliloti. Indentities of major nod inducers were established by spectroscopic analyses (ultraviolet/visible, proton nuclear magnetic resonance, and mass spectroscopy) and comparison with authentic standards. Major nod inducers, which were identified as 4',7-dihydroxyflavone, 4'-7-dihydroxyflavanone, and 4,4'-dihydroxy-2'-methoxychalcone, were released from seedling roots at 54, 22, and 20 picomole.plant(-1).day(-1), respectively. Luteolin was not found in these root exudates. The 4,4'-dihydroxy-2'-methoxychalcone induced nod genes at a concentration one order of magnitude lower than luteolin and is the first naturally released chalcone reported to have this function. Moderate and weak nod-inducing activity was associated, respectively, with 4',7-dihydroxyflavone and 4',7-dihydroxyflavanone.
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/16667146-16453763, http://linkedlifedata.com/resource/pubmed/commentcorrection/16667146-16593884, http://linkedlifedata.com/resource/pubmed/commentcorrection/16667146-16661907, http://linkedlifedata.com/resource/pubmed/commentcorrection/16667146-16665583, http://linkedlifedata.com/resource/pubmed/commentcorrection/16667146-16666315, http://linkedlifedata.com/resource/pubmed/commentcorrection/16667146-2447061, http://linkedlifedata.com/resource/pubmed/commentcorrection/16667146-2980201, http://linkedlifedata.com/resource/pubmed/commentcorrection/16667146-3384804, http://linkedlifedata.com/resource/pubmed/commentcorrection/16667146-3539915, http://linkedlifedata.com/resource/pubmed/commentcorrection/16667146-3597319, http://linkedlifedata.com/resource/pubmed/commentcorrection/16667146-3738520, http://linkedlifedata.com/resource/pubmed/commentcorrection/16667146-3931078
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Nov
pubmed:issn
0032-0889
pubmed:author
pubmed:issnType
Print
pubmed:volume
91
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
842-7
pubmed:dateRevised
2010-9-15
pubmed:year
1989
pubmed:articleTitle
A Chalcone and Two Related Flavonoids Released from Alfalfa Roots Induce nod Genes of Rhizobium meliloti.
pubmed:affiliation
Department of Agronomy and Range Science, University of California, Davis, California 95616.
pubmed:publicationType
Journal Article