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          Institute: MPI für Pflanzenzüchtungsforschung     Collection: Dept. Plant Developmental Biology (George Coupland)     Display Documents

ID: 28756.0, MPI für Pflanzenzüchtungsforschung / Dept. Plant Developmental Biology (George Coupland)
Light-dependent induction of proline biosynthesis by abscisic acid and salt stress is inhibited by brassinosteroid in Arabidopsis
Authors:Abraham, E.; Rigo, G.; Szekely, G.; Nagy, R.; Koncz, C.; Szabados, L.
Date of Publication (YYYY-MM-DD):2003-02
Title of Journal:Plant Molecular Biology
Journal Abbrev.:Plant Mol.Biol.
Issue / Number:3
Start Page:363
End Page:372
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:Osmotic stress-induced accumulation of proline, an important protective osmolyte in higher plants, is dependent on the expression of Delta(1)-pyrroline-5-carboxylate synthase (P5CS) and proline dehydrogenase (PDH) enzymes that catalyze the rate- limiting steps of proline biosynthesis and degradation, respectively. Proline metabolism is modulated by differential regulation of organ specific expression of PDH and duplicated P5CS genes in Arabidopsis. Stimulation of proline synthesis by abscisic acid (ABA) and salt stress correlates with a striking activation of P5CS1 expression. By contrast, P5CS2 is only weakly induced, whereas PDH is inhibited to different extent by ABA and salt stress in shoots and roots of light-grown plants. Proline accumulation and light-dependent induction of P5CS1 by ABA and salt stress is inhibited in dark-adapted plants. During dark adaptation P5CS2 is also down-regulated, whereas PDH expression is significantly enhanced in shoots. The inhibitory effect of dark adaptation on P5CS1 is mimicked by the steroid hormone brassinolide. However, brassinolide fails to stimulate PDH, and inhibits P5CS2 only in shoots. Proline accumulation and induction of P5CS1 transcription are simultaneously enhanced in the ABA-hypersensitive prl1 and brassinosteroid- deficient det2 mutants, whereas P5CS2 shows enhanced induction by ABA and salt only in the det2 mutant. In comparison, the prl1 mutation reduces the basal level of PDH expression, whereas the det2 mutation enhances the inhibition of PDH by ABA. Regulation of P5CS1 expression thus appears to play a principal role in controlling proline accumulation stimulated by ABA and salt stress in Arabidopsis.
Free Keywords:abscisic acid; brassinosteroid; P5CS; proline biosynthesis; salt stress
Comment of the Author/Creator:Date: 2003, FEB
External Publication Status:published
Document Type:Article
Communicated by:N.N.
Affiliations:MPI für Pflanzenzüchtungsforschung
External Affiliations:Hungarian Acad Sci, Biol Res Ctr, Inst Plant Biol, POB; 521,Temesvari Krt 62, H-6701 Szeged, Hungary; Hungarian Acad Sci, Biol Res Ctr, Inst Plant Biol, H-6701 Szeged, Hungary; Max Planck Inst Zuchtungsforsch, D-50829 Cologne, Germany
Identifiers:ISI:000180453200006 [ID No:1]
ISSN:0167-4412 [ID No:2]
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