Effect of salt stress on glycine betaine biosynthesis and catabolism by Medicago sativa bacteroids

Conference · Tue May 01 00:00:00 EDT 1990 · Plant Physiology, Supplement; (USA)

OSTI ID:5851123

Fougere, F; Poggi, M -C; Le Rudulier, D ^[1]

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1. Univ. Nice-Sophia Antipolis (France)

Previous works have shown that glycine betaine (GB) and choline (Cho) are actively taken up by Medicago sativa bacteroids isolated from 4-week-old nodules. Here, we have investigated the effects of NaCl on the fte of Cho and GB. Bacteroids were incubated in low- or high-salt-medium (0.4 M NaCl) and supplemented with {sup 14}C 1,2-Cho or {sup 14}C 1,2-GB. After 3 hours, radioactivity was measured in CO{sub 2} released, in ethanol-soluble and insoluble fractions. In absence of salt, a low proportion of the labelling was found in soluble fraction: 47 and 19% after Cho or GB supply, respectively. On the contrary, in high-salt-medium, the soluble fraction still contained 85% of the radioactivity with GB corresponding to 92-98%. Both enzymes involved in GB biosynthesis from Cho were studied. Choline oxidase activity was enhanced by 59%, while betainal dehydrogenase activity remained unchanged after bacteroid incubation in high-salt-medium. Thus, GB accumulation in salt-stressed bacteroids would be likely a consequence of a decrease of its catabolism rather than an increase of its biosynthesis.

• OSTI ID: 5851123
• Report Number(s): CONF-9007196-; CODEN: PPYSA
• Journal Information: Plant Physiology, Supplement; (USA), Vol. 93:1; Conference: Annual meeting of the American Society of Plant Physiologists, Indianapolis, IN (USA), 29 Jul - 2 Aug 1990; ISSN 0079-2241
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
BETAINE
BIOSYNTHESIS
CATABOLISM
HYPERTONIC SOLUTIONS
BIOLOGICAL EFFECTS
CARBON 14 COMPOUNDS
TRACER TECHNIQUES
AMINES
AMINO ACIDS
AMMONIUM COMPOUNDS
CARBOXYLIC ACIDS
DISPERSIONS
DRUGS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LIPOTROPIC FACTORS
METABOLISM
MIXTURES
ORGANIC ACIDS
ORGANIC COMPOUNDS
QUATERNARY COMPOUNDS
SOLUTIONS
SYNTHESIS
550201* - Biochemistry- Tracer Techniques