Evolutionary insights into strategy shifts for the safe and effective accumulation of ascorbate in plants.
J Exp Bot
; 75(9): 2664-2681, 2024 May 03.
Article
in En
| MEDLINE
| ID: mdl-38452239
ABSTRACT
Plants accumulate high concentrations of ascorbate, commonly in their leaves, as a redox buffer. While ascorbate levels have increased during plant evolution, the mechanisms behind this phenomenon are unclear. Moreover, has the increase in ascorbate concentration been achieved without imposing any detrimental effects on the plants? In this review, we focus on potential transitions in two regulatory mechanisms related to ascorbate biosynthesis and the availability of cellular dehydroascorbate (DHA) during plant evolution. The first transition might be that the trigger for the transcriptional induction of VTC2, which encodes the rate-limiting enzyme in ascorbate biosynthesis, has shifted from oxidative stress (in green algae) to light/photosynthesis (in land plants), probably enabling the continuous accumulation of ascorbate under illumination. This could serve as a preventive system against the unpredictable occurrence of oxidative stress. The second transition might be that DHA-degrading enzymes, which protect cells from the highly reactive DHA in green algae and mosses, have been lost in ferns or flowering plants. Instead, flowering plants may have increased glutathione concentrations to reinforce the DHA reduction capacity, possibly allowing ascorbate accumulation and avoiding the toxicity of DHA. These potential transitions may have contributed to strategies for plants' safe and effective accumulation of ascorbate.
Key words
Full text:
1
Database:
MEDLINE
Main subject:
Plants
/
Ascorbic Acid
/
Biological Evolution
Language:
En
Journal:
J Exp Bot
Journal subject:
BOTANICA
Year:
2024
Type:
Article
Affiliation country:
Japan