The effect of pathogens on plant genome stability
University of Lethbridge. Faculty of Arts and Science
Lethbridge, Alta. : University of Lethbridge, Dept. of Biological Sciences, 2004
Resistance (R) genes, a key factor in determining the resistance of plants, have been shown often to be highly allelic entities existing in duplicated regions of the genome. This characteristic suggests that R-gene acquisition may have arisen through frequent genetic rearrangements as a result of transient, reduced genome stability. Tabacco plants transgenic for a recombination construct exhibited reduced genome stability upon infection with a virulent pathogen (tobacco mosaic virus). The reduced genome stability manifested as an increase in recombination events in the transgene. Such increases were observed following a virulent pathogen attack. This increase in recombination was shown to be systemic and was observed prior to systemic viral movement suggesting the presence of a systemic recombination signal. Further molecular analyses revealed that specific R-gene loci experience a large frequency of rearrangements following a virulent pathogen encounter. The possible targeting of instability to R-gene regions may be controlled through epigenetic processes, in particular, DNA methylation.
xiii, 119 leaves ; 29 cm.
Dissertations, Academic , Plants -- Disease and pest resistance -- Genetic aspects , Plant diseases -- Genetic aspects , Plant molecular genetics