Abscisic (ABA)-aldehyde is a precursor to, and 1 prime ,4 prime -trans-ABA-diol a catabolite of, ABA in apple. [Malus domestica]

Journal Article · Sun Jul 01 04:00:00 EDT 1990 · Plant Physiology; (USA)

DOI:https://doi.org/10.1104/pp.93.3.915· OSTI ID:5914658

Rock, C D; Zeevaart, J A.D. ^[1]

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1. Michigan State Univ., East Lansing (USA)

Previous {sup 18}O labeling studies of abscisic acid (ABA) have shown that apple (Malus domestica Borkh. cv Granny Smith) fruits synthesize a majority of ({sup 18}O)ABA with the label incorporated in the 1{prime}-hydroxyl position and unlabeled in the carboxyl group (JAD Zeevaart, TG Heath, DA Gage (1989) Plant Physiol 91: 1594-1601). It was proposed that exchange of {sup 18}O in the side chain with the medium occurred at an aldehyde intermediate stage of ABA biosynthesis. We have isolated ABA-aldehyde and 1{prime}-4{prime}-trans-ABA-diol (ABA-trans-diol) from {sup 18}O-labeled apple fruit tissue and measured the extent and position of {sup 18}O incorporation by tandem mass spectrometry. {sup 18}O-Labeling patterns of ABA-aldehyde, ABA-trans-diol, and ABA indicate that ABA-aldehyde is a precursor to, and ABA-trans-diol a catabolite of, ABA. Exchange of {sup 18}O in the carbonyl of ABA-aldehyde can be the cause of loss of {sup 18}O from the side chain of ({sup 18}O)ABA. Results of feeding experiments with deuterated substrates provide further support for the precursor-product relationship of ABA-aldehyde {yields} ABA {yields} ABA-trans-diol. The ABA-aldehyde and ABA-trans-diol contents of fruits and leaves were low, approximately 1 and 0.02 nanograms per gram fresh weight for ABA-aldehyde and ABA-trans-diol, respectively, while ABA levels in fruits ranged from 10 to 200 nanograms per gram fresh weight. ABA biosynthesis was about 10-fold lower in fruits than in leaves. In fruits, the majority of ABA was conjugated to {beta}-D-glucopyranosyl abscisate, whereas in leaves ABA was mainly hydroxylated to phaseic acid. Parallel pathways for ABA and trans-ABA biosynthesis and conjugation in fruits and leaves are proposed.

• OSTI ID: 5914658
• Journal Information: Plant Physiology; (USA), Journal Name: Plant Physiology; (USA) Vol. 93:3; ISSN 0032-0889; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ABSCISIC ACID
APPLES
AUXINS
BIOSYNTHESIS
CARBOXYLIC ACIDS
DEUTERIUM COMPOUNDS
EVEN-EVEN NUCLEI
FOOD
FRUITS
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
ISOTOPES
LEAVES
LIGHT NUCLEI
METABOLISM
MONOCARBOXYLIC ACIDS
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXYGEN 18
OXYGEN ISOTOPES
PHYSIOLOGY
PLANT GROWTH REGULATORS
STABLE ISOTOPES
SYNTHESIS
TRACER TECHNIQUES