Tracking Agrobacterium strains by a RAPD system to identify single colonies from plant tumours

Abstract

A molecular typing system for Agrobacterium strains based on the polymerase chain reaction-random amplified polymorphic DNA (PCR-RAPD) procedure was developed. It employs one to four different 10-mer primers and the results are highly reproducible. The band patterns obtained with the four primers for each of the 39 Agrobacterium strains analysed were different enough to differentiate the strains from each other. Strains with similar chromosomal background but different plasmid content, e. g. strains C58 and A281, gave the same band pattern with all the primers. Ten host plants were inoculated with eight Agrobacterium strains and the isolates obtained from the resulting tumours were analysed using the RAPD system developed here. The procedure allowed rapid identification of isolates recovered from tumours by comparison of their band patterns with band patterns of strains used as inoculum. The procedure also discriminated the various strains analysed. Purified bacterial cell suspensions, used for RAPD analyses, produced the same results as purified DNA, and greatly simplified the procedure. This system can be applied for rapid screening of Agrobacterium-like colonies isolated from plant tumours for epidemiological and genetic diversity studies.