Xanthomonas oryzae pathovar oryzae

bacterium

Also known as: Bacillus oryzae, Xoo

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July 21, 2026

Quick Summary

Xanthomonas oryzae pathovar oryzae (Xoo) is a bacterium that causes rice bacterial blight, a devastating disease affecting rice crops worldwide. This disease can lead to significant crop losses, sometimes as high as 75 percent, and infects millions of hectares annually.

Xoo thrives in warm, humid conditions and is found in many rice-growing regions. Symptoms include water-soaked streaks on leaves that develop into grayish-white lesions, causing leaves to dry out and die. In seedlings, this can result in wilting and death within weeks.

The bacteria spread easily through water in flooded rice paddies, infecting neighboring plants. While chemical controls are largely ineffective, resistant rice varieties, developed through the identification of specific resistance genes, have been the most successful method of managing this disease.1

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rice bacterial blight
causal agent, the bacterium Xanthomonas oryzae pathovar oryzae (also referred to as Xoo), was identified in 1911, at that time having been named Bacillus oryzae. Thriving in warm, humid environments, bacterial blight has been observed in rice-growing regions of Asia, the western coast of Africa, Australia, Latin America, and…
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causal agent, the bacterium Xanthomonas oryzae pathovar oryzae (also referred to as Xoo), was identified in 1911, at that time having been named Bacillus oryzae. Thriving in warm, humid environments, bacterial blight has been observed in rice-growing regions of Asia, the western coast of Africa, Australia, Latin America, and…
Read More