The Use of Hairy Roots Transformed by Agrobacterium Rhizogenes for the Production of Plant Secondary Products in Vitro

Abstract

The study of plant secondary metabolism, with the aim of bio-technological exploitation using tissues grown in vitro, has traditionally tended to use dispersed cell cultures or callus. The cultures usually have a strong tendency to be genetically and biochemically unstable and often synthesize very low levels of secondary products. Recently we have begun to study the potential of “hairy root” cultures, resulting from the infection of dicotyledonous plants with Agrobacterium rhizogenes, for the production of secondary products in vitro. We have found that such cultures produce the secondary products synthesized in the roots of the plant species in question in qualitative proportions typical of the parent plant and in quantitative levels at least as high as those found in the plant. Such cultures grow very rapidly in vitroin simple media devoid of phytohormones. They are biochemically stable and we have evidence that their chromosome number remains stable for at least a year in culture.

Such cultures are amenable to genetic mainipulation, raising the possibility of increasing the secondary product synthesizing capacity of hairy roots grown in vitro. Coupled with the inherent biochemical and genetic stability of such tissues, these methods may facilitate the biotechnological exploitation of hairy roots as a source of valuable secondary products.