Research Program

We are studying the genetics and ecology of the soft rot Erwinia. Erwinia carotovora and Erwinia chrysanthemi cause soft rot and wilt diseases in numerous plants, ranging from potatoes to corn to African violets. These diseases are characterized by water soaked lesions and decayed plant tissue that may turn brown or black. We have found that the genomes of E. carotovora strains vary significantly and one of the focuses of our lab is to try to determine what genes vary between strains, what their functions are, and what is driving this variation. Our project titled "Genome-enabled analysis of natural populations of pathogens on natural hosts" addresses these questions.

We have also found that E. chrysanthemi aggregates in culture and that some of the genes required for this aggregation are also required for virulence. We are working on identifying additional genes required for E. chrysanthemi aggregation and determining if these genes are also required for virulence.

We also have several projects focusing on pathogen detection including a collaborative project with investigators at Cornell University (Keith Perry and Chris Smart) titled "Integrated technologies for the rapid diagnosis of known and emerging plant pathogens" and a second collaborative project with researchers in Israel (David Levy) and Morocco (Arifi Aziz) titled "Improvement of local seed potato production in the Middle East."

Details on all of these projects may be found on our lab homepage.

Lab Members

Wisconsin Seed Potato Certification Program

I am also the administrative director of the Wisconsin Seed Potato Certification Program. Much of the early research work on potato diseases and how they spread was done in Germany and Holland around the turn of the century. Scientists found that, through careful monitoring of the crop and removal of unhealthy plants, they could maintain a vigorous, healthy stock indefinitely. Similar research soon was being conducted in the United States. Efforts in Wisconsin led to the establishment of the Wisconsin Seed Improvement Association in 1905. In 1913, the Association decided to support a formal plan for inspection and certification of potato seed. Wisconsin and two other states established official seed potato certification programs in 1913, the first such programs in North America. The Wisconsin Seed Potato Certification Program has been administered since inception by the Department of Plant Pathology, College of Agricultural and Life Sciences, University of Wisconsin - Madison. The program retain a full-time staff of experienced professionals to ensure thoroughness and impartially in inspection and certification procedures.

The Fundamental goal of the Wisconsin seed program and others that have followed is to improve the quality and productivity of commercial potato plantings. A reliable source of high-quality, disease-free basic seed stocks is essential to the strength and growth of a certified seed potato program. The University of Wisconsin Lelah Starks Elite Foundation Seed Potato Farm in Rhinelander has been the Wisconsin seed potato growers' primary source of new and established disease-tested potato varieties since 1983. This 1,000 acre farm is named after Lelah Starks, a pioneer Wisconsin seed potato grower. Certification Program staff are integrally involved in the management of the State Seed Farm, providing not only a concentration of specific expertise in basic seed production, but also accountability to the industry to maintain the highest scientific standards in seed production.

Select Recent Publications

Research Papers

Yap, M.-N, C.-H. Yang, J. D. Barak, C. E. Jahn, and A. O. Charkowski. The Erwinia chrysanthemi type III secretion system is required for multicellular behavior. Accepted to J. Bacteriol. 2004

Yap, M.-N., J. D. Barak, and A. O. Charkowski. Genomic diversity of Erwinia carotovora subsp. carotovora and its correlation with virulence. Appl. Environ. Microbiol. 60:3013-3023. 2004.

Reviews and Editorials

Charkowski, A. O. Making sense of an alphabet soup: the use of a new bioinformatics tool for identification of novel gene islands. Physiological Genomics 16:180-181. 2004.

Futher publications can be found on the Charkowski Lab Website.