Daucus carota L. (Carrot): In Vitro Production of Carotenoids and Phytoalexins

Abstract

Daucus carota (family Umbelliferae) is one of the most commonly used plant materials in tissue culture studies. Although various aspects of growth and organization have been extensively studied, relatively few attempts have been made at in vitro production of specific plant ingredients in carrot cells. Carrot root is characterized by its high content of carotenoid pigments. Carotenoids are also found in petals, seeds, and fruits of various plant species. Many of the yellow, orange, and red colors seen in these plant organs are often due to the presence of these compounds. The distribution of carotenoids in higher plants has been summarized by (1976) and (1980). However, their occurrence is not restricted to those storage organs but includes all parts of the plant. They serve as light-harvesting molecules in photosynthetic organelles and also play a role in protecting prokaryotes from the deleterious effects of light. Carotenoids are also essential for vision. The light-absorbing molecules of the visual system in many organisms, 11-cis-retinal, is derived from β-carotene. Carotenbids have been shown to be anti-carcinogenous in rats and mice, and it also appears to be the case in humans (Ames 1983). Although β-carotene is currently produced synthetically for commercial use, carrot cell cultures offer a very useful model system in studying the in vitro production of important plant metabolites.