Tomato pathogen genome may offer clues about bacterial evolution at dawn of a...( Blacksburg Va. The availability of ...)

Blacksburg, Va. The availability of new genome sequencing technology has prompted a Virginia Tech plant scientist to test an intriguing hypothesis about how agricultures early beginnings may have impacted the evolution of plant pathogens.

Boris Vinatzer, assistant professor of plant pathology, physiology, and weed science in the College of Agriculture and Life Sciences, has received a $1 million, five-year Faculty Early Career Development (CAREER) award from the National Science Foundation (NSF) to investigate the pathogen that causes bacterial speck disease of tomatoes and to develop a new undergraduate course in microbial genomics.

Little is known about how plant pathogens, which were adapted to natural mixed-plant communities in pre-agriculture times, evolved into todays highly aggressive pathogens of crops cultivated in monoculture, Vinatzer said. To fill this void, this project aims at identifying the molecular evolutionary mechanisms that allow pathogens to specialize to specific plant species and to become more aggressive.

In 2007, Vinatzer sequenced the genome of a Pseudomonas syringae pv. tomato strain using technology from the Virginia Bioinformatics Institute (VBI) at Virginia Tech and funding from the universitys Institute for Biomedical and Public Health Sciences. The tomato pathogen was the first genome to be sequenced on the new Roche GS-FLX machine, which VBI had just purchased with Virginias Commonwealth Research Initiative funding.

That sequence, in addition to other preliminary data, allowed me to develop a hypothesis on the evolution of plant pathogenic bacteria since the beginning of agriculture, Vinatzer said. The hypothesis is that plant pathogenic bacteria evolved from relatively weak pathogens that caused disease in many plants to specialized highly virulent pathogens of single crops after entire fields of the same plant species became available to them in agricultural fields. Importantly, understand
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