Disturbed correlation between fungal biomass and beta -glucuronidase activity in infections of Arabidopsis thaliana with transgenic Alternaria brassicicola

摘要

Several previous studies have described the use of the bacterial uidA ( beta -glucuronidase) gene to transform fungal pathogens of plants. In many cases beta -glucuronidase activity has been considered as a quantitative parameter for the extent of development of uidA-expressing transgenic fungi in infected plants. Here we present evidence that this method is not applicable in all plant-pathogen interactions. In Arabidopsis plants inoculated with an uidA-expressing transgenic Ahernaria brassicicola fungus, there was a good correlation between lesion development and the level of uidA mRNA whereas beta -glucuronidase activity dropped as lesions extended. This indicates that plant factors accumulating or released during lesion development can interfere with beta -glucuronidase activity in the fungus.