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Citrus canker is a disease affecting ''Citrus'' species caused by the bacterium ''Xanthomonas axonopodis''. Infection causes lesions on the leaves, stems, and fruit of citrus trees, including lime, oranges, and grapefruit. While not harmful to humans, canker significantly affects the vitality of citrus trees, causing leaves and fruit to drop prematurely; a fruit infected with canker is safe to eat, but too unsightly to be sold. The disease, which is believed to have originated in Southeast Asia, is extremely persistent when it becomes established in an area. Citrus groves have been destroyed in attempts to eradicate the disease. Brazil and the United States are currently suffering from canker outbreaks. == Biology == ''Xanthomonas axonopodis'' is a rod-shaped Gram-negative bacterium with polar flagella. The bacterium has a genome length around 5 megabase pairs. A number of types of citrus canker diseases are caused by different pathovars and variants of the bacterium:〔Gottwald, T.R, Graham, J.H. and Schubert, J.S. (2002). (Citrus canker: The pathogen and its impact ). Online. ''Plant Health Progress'' 〕 *The Asiatic type of canker (canker A), ''X. axonopodis'' pv. ''citri'', caused by a group of strains originally found in Asia, is the most widespread and severe form of the disease. *Cancrosis B, caused by a group of ''X. axonopodis'' pv. ''aurantifolii'' strains originally found in South America is a disease of lemons, key lime, bitter orange, and pomelo. *Cancrosis C, also caused by strains within ''X. axonopodis'' pv. ''aurantifolii'', only infects key lime and bitter orange. *A * strains, discovered in Oman, Saudi Arabia, Iran, and India, only infect key lime. 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「Citrus canker」の詳細全文を読む スポンサード リンク
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