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''Clavibacter michiganensis'' is an aerobic non-sporulating Gram-positive plant pathogenic actinomycete that currently constitutes the only species within the genus ''Clavibacter''. The other former ''Clavibacter'' species have been reclassified to genera ''Leifsonia'', ''Rathayibacter'' and ''Curtobacterium''. ''Clavibacter michiganensis'' currently has five subspecies; all are available from the NCPPB for legitimate researchers: ''Clavibacter michiganensis'' subsp. ''insidiosus'', ''Clavibacter michiganensis'' subsp. ''michiganensis'', ''Clavibacter michiganensis'' subsp. ''nebraskensis'', ''Clavibacter michiganensis'' subsp. ''sepedonicus'' and ''Clavibacter michiganensis'' subsp. ''tesselarius''. ''Clavibacter michiganesis'' subsp. ''michiganensis'' and ''Clavibacter michiganesis'' subsp. ''sepedonicus'' are the main diseases that cause substantial economic losses worldwide by damaging tomatoes and potatoes.〔Gartemann et al. "Clavibacter michiganensis subsp. michiganensis: first steps in the understanding of virulence of a Gram-positive phytopathogenic bacterium", ''Journal of Biotechnology'', Germany, 16 July 2003. Retrieved on 2011-10-26.〕 == Context == Clavibacter is an unusual genera of phytopathogenic bacteria in that it is gram-positive and does not have a type 3 secretion system. All Clavibacter species and subspecies have a type B2γ cell wall crosslinked at a diaminobutyrate residue. Clavibacter is an aerobic bacterium with a coryneform morphology. There is no mycelium and no spores are produced.〔 Clavibacter michiganensis infects the primary host in one of three ways: wounds, hydathodes, or by contaminated seed. If the bacteria reach a suitable quorum, the result is a systemic vascular infection. In the first stages of invasion, Clavibacter michiganensis resides as a biotrophic pathogen in the xylem vessels.〔 ''Clavibacter'' has a complex history of taxonomical names. There is only one recognized species within the genus Clavibacter. There are now five recognized subspecies, or strains, within the ''michiganensis'' species. Recently, some strains have been reclassified into other genera. This complex history stems from the difficulty in characterizing bacteria. Unlike fungi, the morpholology of bacteria is not very sufficient for taxonomical purposes. To this end, strains of a phytopathogenic bacteria, called pathovars, are distinguished by cultural (selective media), physiological, biochemical (e.g. secreted enzymes the chemical responses of the plant), or pathological characteristics (including the range of susceptible hosts).〔Eichenlaub R, Gartemann K-H, Burger A. 2006 ''Clavibacter michiganensis'', a group of Gram positive phytopathogenic bacteria. In "Plant-Associated Bacteria", ed. SS Gnanamanickam, pp. 385-422. Dordrecht: Springer〕 Recently, two strains of this bacteria - subsp. sepidonicum and subsp. michiganensis - have had their genomes sequenced and annotated. There is still much to discover about this pathogen-host interaction but now that the genome has been sequenced, the rate of discoveries will likely increase. One of the main goals pertaining to research of these bacterial genomes is to develop resistant varieties. Unfortunately, no resistant varieties have yet been found.〔Coaker GL, Willard B, Kinter M, Stockinger EJ, Francis DM. 2004. Proteomic analysis of resistance mediated by Rem 2.0 and Rem 5.1, two loci controlling resistance to bacterial canker of tomato. Mol. Plant-Microbe Interact. 17: 1019-28〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Clavibacter michiganensis」の詳細全文を読む スポンサード リンク
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