Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: January 12, 2003
Publication Date: June 12, 2003
Citation: LUSTER, D.G., BRUCKART, W.L., YOURMAN, L., MCMAHON, M.B. GENOTYPING OF PATHOGENS WITH POTENTIAL FOR BIOLOGICAL CONTROL OF INVASIVE WEEDS. XI International Symposium of biological Control of Weeds. p118, #68. 2003. Technical Abstract: Genetic characterization of microbial biological control agents is an essential part in the process of evaluation and release, allowing researchers to identify and discriminate between beneficial plant pathogen strains for purposes of release monitoring, risk assessment and liability.We have applied molecular techniques with proven utility in plant pathology to the analysis of fungal pathogens considered for release as biological controls for invasive weeds. We have utilized both Amplified Fragment Length Polymorphism (AFLP) and Random Amplified Microsatellites (RAMS) to characterize Puccinia jaceae, a rust fungal pathogen of Centaurea solstitialis (yellow starthistle; YST). Unique AFLP patterns were identified for a P. jaceae strain targeted for release on YST in California, USA. PCR primers were engineered from the DNA sequence of a RAMS amplicon generated by PCR from the P. jaceae strain. The primers were found to be specific for the P. jaceae strain and thus will prove useful in monitoring the spread and establishment of the pathogen once released. Ribosomal RNA gene Internal Transcribed Spacer (ITS) regions were sequenced from Puccinia carduorum, a rust fungal pathogen of Carduus thoermeri (musk thistle). Discrete differences in DNA sequence were identified between strains of P. carduorum, allowing us to discriminate between those specific to individual Carduus host species. ITS sequencing was subsequently applied to the identification and monitoring of a P. carduorum strain released in Virginia USA, which has since spread as far west as California, USA. The application of such "genotyping" techniques to the study of beneficial weed pathogens illustrate the potential of the techniques and their utility in practical post-release applications.