Clavibacter michiganensis

Classification

Domain: Bacteria, Phylum: Actinobacteria, Class: Actinobacteria, Subclass: Actinobacteridae, Order: Actinomycetales, Suborder: Micrococcineae, Family: Microbacteriaceae, Genus: Clavibacter, Species: michiganensis, Subspecies: sepedonicus

Species

Clavibacter michiganensis subsp. sepedeonicus

Description and Significance

Describe the appearance, habitat, etc. of the organism, and why you think it is important.

Genome Structure

Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence?

Cell Structure, Metabolism and Life Cycle

Clavibacter michiganensis subsp. sepedonicus is a gram positive bacteria (Li and Deboer, 1995). It is pleomorphic, slightly club-shaped short rod and this rod size is about 0.5 - 1.0 µm. C.m. sepedonicus is aerobic pathogen but it also can grow slowly in anaerobic condition. The isolated colonies are often yellow, creamy and smooth (Van der Wolf J.M et al, 2005). C.m. sepedonicus infects the healthy plant through wounds. It moves from plant to plant in irrigation water or insect vectors such as Colorado potato beetles and flea beetles. C.m. sepedonicus is soil invader pathogen. The pathogens overwinter in tuber seeds and favor in high temperature at the end of growing season. It can survive in tuber seeds, plant debris and on agricultural equipments. It can survive up to 10 days in surface water and up to 5 years in dried and cold climate (Sparks A. and Megan K., 2008) and. However, if the temperature increases up to 150C, the pathogen can survive only for few weeks (Van der Wolf J.M. et al, 2005). The C.m. sepedonicus gene was found 90% identity of Clavibacter michiganensis subsp. Michiganensis. This gene was found in a protein which was coded from over 700 amino acids (Van der Wolf J.M et al, 2005).

Ecology and Pathogenesis

C.m. sepedonicus's infection is mainly on potato, less in tomato and eggplant, sometime in root of sugar beet. In potato, it causes ring rot in tuber seeds. This disease was first found in Germany in the late 1800's. Then the pathogen was presented into United States in the early 1930's and spread out whole the country by 1940's (Randall C. Rowe et al, 1995). The disease severity can cause wilting of leaf and stem, chlorosis and necrosis from leaf margins. C.m. sepedonicus produces amylase and cellulase enzymes. Amylase enzyme is used to break drown starch into sugar and cellulase is responsible for the hydrolysis of the cellulose polymer into dimeric subunits. Cellulase was also proven as an important virulence factor for C.m. sepedonicus (Van der Wolf J.M et al, 2005).

References

Li X.A., Deboer S.H. (1995). Selection of polymerase chain-reaction primers from an RNA intergenic spacer region for specific detection of Clavibacter michiganensis subsp. sepedonicus. Phytopathology 85:837-842.

Randall C. Rowe , Sally A. Miller, Richard M. Riedel, 1995. Bacterial Ring Rot of Potatoes. Ohio State University Extension Fact Sheet HYG-3103-95

Sparks A. and Kennelly M. (2008). Bacterial Ring Rot of Potato, Kansas State University, August 2008.

Van der Wolf J.M., Elphinstone J. G., Stead D. E., Metzler M., Muller P., Hukkenen A., Karjalainen R., 2005. Epidemiology of Clavibacter Michiganensis subsp. sepedonicus in relation to control of bacterial ring rot. Plant Research International B.V., Wageningen.

Author

Page authored by Ninh Hoang and , student of Prof. Jay Lennon at Michigan State University.