Innovative in vitro plant methodologies for biosynthesis and isolation of tomato carotenoids

Abstract

An overall goal of our laboratory is the development of in vitro plant tissue culture techniques for the biosynthesis of natural carotenoids, which can be administered in metabolism studies. Previously, we developed a novel approach utilizing a tomato cell suspension culture system (Lycopersicon esculentum cv. VFNT Cherry), which after incorporation of a phytoene desaturase inhibitor, norflurazon, to cell culture medium, yielded a drastic increase in accumulation of both phytoene (PE) and phytofluene (PF). To further optimize PE and PF in vitro production, we have recently established callus cell cultures from both leaf and flower bud tissue of the tomato ghost variegation mutant, which has demonstrated high tomato fruit accumulation of PE. In a similar manner, high lycopene (LYC) producing tomato mutants, including high pigment-1, high pigment-2, and old gold, as well as the wild species Lycopersicon pimpinellifolium, were adapted as in vitro cell cultures to determine whether similarly enhanced LYC would accumulate in the elite tomato cell lines. To maximize the cost efficiency of radiolabeled carotenoid production, cell cultures were monitored to determine the points of maximal carotenoid biosynthesis during the growth cycle. The novel methodologies utilizing plant tissue culture techniques will provide sources of tomato carotenoids in their natural isomeric forms for future studies evaluating the bioavailability, metabolism, and accumulation of these compounds and their metabolites. (Supported by NIH/NCI CA 112649-01A1)