Concurrent synthesis and release of nod-gene-inducing flavonoids from alfalfa roots. [Medicago sativa L. ; Rhizobium meliloti]

Journal Article · Wed Aug 01 00:00:00 EDT 1990 · Plant Physiology; (USA)

DOI:https://doi.org/10.1104/pp.93.4.1552· OSTI ID:5924543

Maxwell, C A; Phillips, D A ^[1]

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1. Univ. of California, Davis (USA)

Flavonoid signals from alfalfa (Medicago sativa L.) induce transcription of nodulation (nod) genes in Rhizobium meliloti. Alfalfa roots release three major nod-gene inducers: 4{prime},7-dihydroxyflavanone, 4{prime},7-dihydroxyflavone, and 4,4{prime}-dihydroxy-2{prime}-methoxychalcone. The objective of the present study was to define temporal relationships between synthesis and exudation for those flavonoids. Requirements for concurrent flavonoid biosynthesis were assessed by treating roots of intact alfalfa seedlings with (U-{sup 14}C)-L-phenylalanine in the presence or absence of the phenylalanine ammonia-lyase inhibitor L-2-aminoxy-3-phenylpropionic acid (AOPP). In the absence of AOPP, each of the three flavonoids in exudates contained {sup 14}C. In the presence of AOPP, {sup 14}C labeling and release of all the exuded nod-gene inducers were reduced significantly. AOPP inhibited labeling and release of the strongest nod-gene inducer, methoxychalcone, by more than 90%. The release process responsible for exudation of nod-gene inducers appears to be specific rather than a general phenomenon such as a sloughing off of cells during root growth.

• OSTI ID: 5924543
• Journal Information: Plant Physiology; (USA), Vol. 93:4; ISSN 0032-0889
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ALFALFA
NITROGEN FIXATION
FLAVENOIDS
BIOCHEMICAL REACTION KINETICS
CARBON 14 COMPOUNDS
COPPER CHLORIDES
GENES
PHENYLALANINE
RHIZOBIUM
ROOTS
TRACER TECHNIQUES
TRANSCRIPTION
AMINO ACIDS
BACTERIA
CARBOXYLIC ACIDS
CHLORIDES
CHLORINE COMPOUNDS
COPPER COMPOUNDS
COPPER HALIDES
HALIDES
HALOGEN COMPOUNDS
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
LEGUMINOSAE
MAGNOLIOPHYTA
MAGNOLIOPSIDA
MICROORGANISMS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PLANTS
REACTION KINETICS
TRANSITION ELEMENT COMPOUNDS
550201* - Biochemistry- Tracer Techniques