Impact of Reduced O-Acetylserine(thiol)lyase Isoform Contents on Potato Plant Metabolism
Open Access
- 1 March 2005
- journal article
- Published by Oxford University Press (OUP) in Plant Physiology
- Vol. 137 (3) , 892-900
- https://doi.org/10.1104/pp.104.057125
Abstract
Plant cysteine (Cys) synthesis can occur in three cellular compartments: the chloroplast, cytoplasm, and mitochondrion. Cys formation is catalyzed by the enzyme O-acetylserine(thiol)lyase (OASTL) using O-acetylserine (OAS) and sulfide as substrates. To unravel the function of different isoforms of OASTL in cellular metabolism, a transgenic approach was used to down-regulate specifically the plastidial and cytosolic isoforms in potato (Solanum tuberosum). This approach resulted in decreased RNA, protein, and enzymatic activity levels. Intriguingly, H2S-releasing capacity was also reduced in these lines. Unexpectedly, the thiol levels in the transgenic lines were, regardless of the selected OASTL isoform, significantly elevated. Furthermore, levels of metabolites such as serine, OAS, methionine, threonine, isoleucine, and lysine also increased in the investigated transgenic lines. This indicates that higher Cys levels might influence methionine synthesis and subsequently pathway-related amino acids. The increase of serine and OAS points to suboptimal Cys synthesis in transgenic plants. Taking these findings together, it can be assumed that excess OASTL activity regulates not only Cys de novo synthesis but also its homeostasis. A model for the regulation of Cys levels in plants is proposed.Keywords
This publication has 66 references indexed in Scilit:
- Overproduction of SAT and/or OASTL in transgenic plants: a survey of effectsJournal of Experimental Botany, 2004
- Lysine Metabolism Is Concurrently Regulated by Synthesis and Catabolism in Both Reproductive and Vegetative TissuesPlant Physiology, 2004
- Use of Biomolecular Interaction Analysis to Elucidate the Regulatory Mechanism of the Cysteine Synthase Complex fromArabidopsis thalianaJournal of Biological Chemistry, 2002
- Transgenic tobacco plants expressing a rice cysteine synthase gene are tolerant to toxic levels of cadmiumJournal of Plant Physiology, 2001
- Metabolic Profiling Allows Comprehensive Phenotyping of Genetically or Environmentally Modified Plant SystemsPlant Cell, 2001
- Regulation of sulfate transport and synthesis of sulfur-containing amino acidsCurrent Opinion in Plant Biology, 2000
- Molecular cloning and expression analyses of mitochondrial and plastidic isoforms of cysteine synthase (O-acetylserine(thiol)lyase) fromArabidopsis thalianaAmino Acids, 1999
- Separation, subcellular location and influence of sulphur nutrition on isoforms of cysteine synthase in spinachJournal of Experimental Botany, 1998
- A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye bindingAnalytical Biochemistry, 1976
- Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4Nature, 1970