Journal
PLANT PHYSIOLOGY
Volume 137, Issue 3, Pages 892-900Publisher
AMER SOC PLANT BIOLOGISTS
DOI: 10.1104/pp.104.057125
Keywords
-
Categories
Ask authors/readers for more resources
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 downregulate specifically the plastidial and cytosolic isoforms in potato (Solanum tuberosum). This approach resulted in decreased RNA, protein, and enzymatic activity levels. Intriguingly, H,S-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.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available