Potential of flow cytometry for monitoring genetic stability of banana embryogenic cell suspension cultures

Abstract

Cell suspensions are the material of choice for rapid multiplication and for genetic engineering strategies such as in vitro mutagenesis and genetic transformation. Effective use of cell suspension cultures relies on the knowledge of several key parameters, which include genetic stability, kinetics of the cell cycle and a mode of plant regeneration. Here we report on the use of DNA flow cytometry for quality monitoring of banana cell suspension cultures. The method facilitates detection of ploidy changes and the occurrence of aneuploidy, which result in somaclonal variation of cell-suspension-derived plants. Flow cytometry could also be used to analyse the cell cycle kinetics by calculating the ratio of cells in the G2 and G1 phase of the cell cycle. This is important to determine the most appropriate moment for mutagenic treatment or for genetic transformation but also as an indicator on the proportion of cycling cells. In addition, the unicellular origin of somatic embryos was verified by treating embryogenic cell suspensions with colchicine and by determining the ploidy of regenerated plants by flow cytometric analysis. None of the plants regenerated from colchicine-treated embryogenic cell suspensions were mixoploid (chimeric). The application of flow cytometry will be discussed in relation to (a) the monitoring of genetic instability in DNA content of cell suspensions (b) the analysis of cell cycle and (c) the origin of somatic embryos of bananas and plantains.