Ascorbic acid: a metabolite switch for designing stress-smart crops

Abstract

Plant growth and productivity are continually being challenged by a diverse array of abiotic stresses, including: water scarcity, extreme temperatures, heavy metal exposure, and soil salinity. A common theme in these stresses is the overproduction of reactive oxygen species (ROS), which disrupts cellular redox homeostasis causing oxidative damage. Ascorbic acid (AsA), commonly known as vitamin C, is an essential nutrient for humans, and also plays a crucial role in the plant kingdom. AsA is synthesized by plants through the d-mannose/l-galactose pathway that functions as a powerful antioxidant and protects plant cells from ROS generated during photosynthesis. AsA controls several key physiological processes, including: photosynthesis, respiration, and carbohydrate metabolism, either by acting as a co-factor for metabolic enzymes or by regulating cellular redox-status. AsA’s multi-functionality uniquely positions it to integrate and recalibrate redox-responsive transcriptional/metabolic circuits and essential biological processes, in accordance to developmental and environmental cues. In recognition of this, we present a systematic overview of current evidence highlighting AsA as a central metabolite-switch in plants. Further, a comprehensive overview of genetic manipulation of genes involved in AsA metabolism has been provided along with the bottlenecks and future research directions, that could serve as a framework for designing “stress-smart” crops in future.

Keywords:

• Genetic manipulation
• hormones
• metabolism
• ROS-gradient
• signaling
• stress tolerance

Acknowledgements

AS acknowledges the JRF fellowship support from DAE. The authors would like to thank Mrs. Pooja Negi for critical reading of the manuscript.

Author contributions

SM: Literature survey, manuscript writing, and prepared figures and table; AS: literature survey and manuscript writing; AKS: conceived the idea, manuscript editing, and final approval of the version to be submitted.

Disclosure statement

All the authors declare no conflict of interest.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.