Steve Conaway’s March 2011 trip to Cereal Disease Laboratory at University of Minnesota

Posted: January 1, 2012

With the assistance of the plant pathology departmental travel award Steve had the opportunity to travel to the USDA Cereal Disease Laboratory in March of 2011 and observe techniques used by the world's preeminent rust researchers. The scientists at the CDL were kind enough to explain the details of their work as well as provide helpful suggestions pertaining to my research questions. Although Steve does not work with cereal diseases, his research on Canada thistle biological control with the rust fungus Puccinia punctiformis considers many of the same issues that the CDL focuses on with rust diseases on grain. Topics that have become the center of Steve’s biological control research such as host resistance, virulence genes, dispersal characteristics and epidemiology have all been intensively studied for rust diseases of cereal crops.
Dr. Yui Jin explains the ratings scale developed for quantifying host resistance to wheat rust.  Differences in symptom expression and pustule size are associated with a definitive disease scale.

Dr. Yui Jin explains the ratings scale developed for quantifying host resistance to wheat rust. Differences in symptom expression and pustule size are associated with a definitive disease scale.

The experience at the CDL offered valuable exposure to the most current techniques and successful strategies in rust disease research.  The hands-on experience with rust inoculation, spore harvesting, preservation, and pathogenicity assessment techniques was far more helpful than trying to glean this technical information from the methods sections of journal articles. 

 Steve presented a seminar on his biological control research at the CDL.  He received very interesting feedback.  The scientists at the CDL were interested in the unique thistle rust pathosystem and intrigued with the variety of unknowns.  The contemporary cereal rust research relies on standardized protocols and scientific understanding built on decades of cumulative knowledge.  His work on P. punctiformis has dramatically less background information with a veritable genetic black box.  In this way, he does not expect to reach the same level of specificity in determining pathogenic races of P. punctiformis but any evidence of differential host resistance would be informative in understanding the success or failure of this organism as a biocontrol agent.

Talking to CDL researchers helped in thinking about an experimental approach to studying pathogen biology and host resistance.  He was excited to meet with Dr. Alan Roelfs, coauthor of the definitive rust text The Cereal Rusts and a contemporary of Norman Borlaug.  Dr. Roelfs gave Steve some good ideas on ways to investigate infection strategies of P. punctiformis and cereal rusts that could serve as model organisms.  Dr. Les Szabo gave him valuable critiques on molecular protocols for analysis of rust and thistle genetic diversity.  Drs. Yui Jin, Marty Carson and Matthew Rouse showed him techniques that could be applied to increasing pure lines of P. punctiformis and developing a rating system for testing them against different genotypes of Canada thistle.  Steve was able to meet with Dr. Jeanie Katovich and get some insights into working with exotic pathogens as they do in the biosecurity level 3 containment greenhouse.  These are valuable skills when investigating new potential biocontrol agents. 

In addition to interacting with the staff at the CDL, Steve met with a number of scientists at the University of Minnesota that worked directly with Canada thistle biological control and toured some of their experimental field sites.  He was able to get a number of suggestions in order to avoid repeating research dead-ends that they had encountered.  They discussed other potential biocontrol organisms.

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