Link to home


Modes of seed infection by Clavibacter michiganensis subsp. michiganensis and population diversity in New York.
M. A. TANCOS (1), C. D. Smart (1). (1) Cornell University, Geneva, NY, U.S.A.

Bacterial canker, caused by <i>Clavibacter michiganensis</i> subsp. <i>michiganensis</i>, is an economically devastating seed-borne pathogen that inflicts considerable damage throughout all major tomato-producing nations. Understanding the movement of <i>C. michiganensis</i> subsp.<i> michiganensis</i> both microscopically and geographically will help characterize population diversity, virulence, and modes of infection. In order to investigate the mode of seed infection, New York <i>C. michiganensis</i> subsp. <i>michiganensis</i> field strains were stably transformed with eGFP. <i>C. michiganensis</i> subsp. <i>michiganensis</i> was able to access the developing seeds either i) systemically through the xylem and/or ii) externally by entering fruit through lesions on the pericarp. <i>C. michiganensis</i> subsp. <i>michiganensis</i> cells were located within the developing seed, endosperm, and funiculus, although at relatively low levels compared with the large numbers of cells observed in xylem and pericarp cells; thereby, highlighting the difficulty in detecting and eradicating small initial pathogen populations within seed lots. Furthermore, multilocus sequencing typing revealed a high level of <i>C. michiganensis</i> subsp. <i>michiganensis</i> diversity in New York with approximately 20 unique sequence types. Unique differences were also evident in virulence and plasmid profiles.

View Presentation