Chapter 29 Instability of Chromosomes and Alkaloid Content in Cell Lines Derived From Single Protoplasts of Cultured Coptis Japonica Cells

Abstract

Publisher Summary Genetic homogeneity in cultured cell systems is essential for research on plant cells. Such uniformity is particularly important when studying the regeneration of plants with constant chromosome numbers and for stabilizing the production of useful compounds in cultured cells. Deus and Zenk suggested that the different rates of alkaloid production that they found in the cell lines of Catharanthus roseus were related to a high frequency of chromosome aberrations. Chromosome instability as an aspect of genetic variation in cultured cells, however, is a common phenomenon in many plant species. Yet there have been only a few reports that describe chromosome stabilization in plant cell cultures. Cloning of single protoplasts or single cells can be used to reduce the genetic heterogeneity of cell populations and to obtain cell lines that produce useful compounds. Studies of chromosome stability in the root tips of some plant species derived from protoplasts have been reported. Both normal and abnormal chromosome numbers were found in these regenerated plants. But little information is available on chromosome numbers in callus tissue derived from single protoplasts. This chapter presents the cytogenetic evidence that a variation in chromosome number occurred in one of the cell clones (derived from 27 single protoplast-derived cell lines of Coptis japonica Makino that are characterized by their various chromosomal traits) after 6 months of subculture. It also discusses the fact that there seems to be no correlation among this variation in chromosome number and the production of berberine in the cell.