Arkansas State University, Arkansas Biosciences Institute and Department of Chemistry and Physics, 504 University Loop East, Jonesboro AR 72401. PO Box 639, State University, AR 72467. Jonesboro, Arkansas, USA.
RESUMEN (ABSTRACT)
Vitamin C (ascorbic acid, AsA) is the most abundant water soluble antioxidant and is essential for numerous metabolic processes in animals and plants. Humans have lost the capacity to synthesize it, and plant-derived AsA is thus the major source of vitamin C in the human diet. Although ascorbic acid can be considered an old molecule, the elucidation of how plants make this essential antioxidant is a recent discovery. In addition to its essential role as an antioxidant, in plants AsA also serves as a cofactor of important enzymes, and contributes to the regulation of cell division and expansion, flowering, and senescence. Four biosynthetic pathways leading to AsA formation are known to function in plants, one of them proposed by our group involving myo-inositol as the main precursor. I will present our progress on the development and characterization of Arabidopsis plants with elevated vitamin C levels. We have found that these plants are more tolerant to salt, cold, heat, high light, and methyl viologen when compared to controls. They also display enhanced growth of both aerial and underground tissues, higher seed production, delayed senescence, and tolerance to common environmental pollutants such as trichloroethylene, a chlorinated hydrocarbon, and pyrene, a model polycyclic aromatic hydrocarbon. We are currently expanding the knowledge and concepts we have learned in Arabidopsis to crops of importance such as tomato and rice. New avenues in our research program that I will discuss include: a) investigating the cross talk between the vitamin C and the jasmonates metabolic networks; b) investigating how our high-AsA lines respond when challenged with herbivores, and c) studying the role of AsA in supporting higher production and accumulation of complex proteins in plants.