7 Mutagenesis in Arabidopsis

Abstract

Mutagenesis can be described as the process of inducing any heritable change in the genetic material which is subsequently transmitted to daughter cells where it gives rise to a mutant cell or individual (Rieger et al. 1976). The use of classical mutagenic agents, e.g., ethylmethane sulfonate, nitrosoguanidine, nitrosourea, and X-ray, has resulted in thousands of mutants in Arabidopsis (see McKelvie 1962; Rédei 1970). Considerable insight has been gained about plant developmental and physiological processes from the characterization of some of these mutants. Recently developed technologies make it possible to clone genes from interesting mutants. The use of restriction fragment length polymorphism (RFLP) maps (Chang et al. 1988; Nam et al. 1989; Reiter et al. 1992), for example, makes it possible, although laborious, to isolate genes mutated with these agents (Arondel et al. 1992; Giraudat et al. 1992; Chang et al. 1993). Positional cloning will become increasingly expedient as more molecular markers are positioned on the map and as the physical map nears completion. Another recent technique, genomic subtraction, can be utilized to isolate the affected gene when deletion mutagens are employed, e.g., diepoxybutane and γ irradiation (Sun et al. 1992). However, current technical limitations may make it difficult to isolate large numbers of genes with this technique. Chemical and physical agents and their mutagenic activities are discussed because of their historical and continued usefulness.

Mutagens that have found wide popularity among molecular biologists are insertion mutagens, T-DNAs or transposons (van Sluys et al. 1987; Feldmann 1991). These mutagens provide a...