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Trehalose metabolism in Arabidopsis: occurrence of trehalose and molecular cloning and characterization of trehalose-6-phosphate synthase homologues.

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  • 2001-08-25
Published in:
  • Journal of experimental botany. - 2001
Amino Acid Sequence
Arabidopsis
Cloning, Molecular
Expressed Sequence Tags
Gas Chromatography-Mass Spectrometry
Glucosyltransferases
Molecular Sequence Data
Multienzyme Complexes
Phosphoric Monoester Hydrolases
Plant Roots
Plant Stems
Protoplasts
Saccharomyces cerevisiae
Sequence Deletion
Sequence Homology, Amino Acid
Tobacco
Trehalose
English Axenically grown Arabidopsis thaliana plants were analysed for the occurrence of trehalose. Using gas chromatography-mass spectrometry (GC-MS) analysis, trehalose was unambiguously identified in extracts from Arabidopsis inflorescences. In a variety of organisms, the synthesis of trehalose is catalysed by trehalose-6-phosphate synthase (TPS; EC 2.4.1.15) and trehalose-6-phosphate phosphatase (TPP; EC 3.1.3.12). Based on EST (expressed sequence tag) sequences, three full-length Arabidopsis cDNAs whose predicted protein sequences show extensive homologies to known TPS and TPP proteins were amplified by RACE-PCR. The expression of the corresponding genes, AtTPSA, AtTPSB and AtTPSC, and of the previously described TPS gene, AtTPS1, was analysed by quantitative RT-PCR. All of the genes were expressed in the rosette leaves, stems and flowers of Arabidopsis plants and, to a lower extent, in the roots. To study the role of the Arabidopsis genes, the AtTPSA and AtTPSC cDNAs were expressed in Saccharomyces cerevisiae mutants deficient in trehalose synthesis. In contrast to AtTPS1, expression of AtTPSA and AtTPSC in the tps1 mutant lacking TPS activity did not complement trehalose formation after heat shock or growth on glucose. In addition, no TPP function could be identified for AtTPSA and AtTPSC in complementation studies with the S. cerevisiae tps2 mutant lacking TPP activity. The results indicate that while AtTPS1 is involved in the formation of trehalose in Arabidopsis, some of the Arabidopsis genes with homologies to known TPS/TPP genes encode proteins lacking catalytic activity in trehalose synthesis.
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  • English
Open access status
green
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Persistent URL
https://sonar.ch/global/documents/184397
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