Researchers Discover New Anti-Virulence Agent to Control Fire Blight Disease

Researchers at Hanyang University in Seoul, South Korea, have identified a new anti-virulence agent, tizoxanide, to control fire blight disease caused by Erwinia amylovora, a bacterium that affects apple, pear, and other rosaceous plants. The study aimed to discover new anti-virulence agents to prevent the pathogenesis of this plant bacterial disease. After screening 2485 small molecules, tizoxanide was found to be a potent inhibitor of the type III secretion system (T3SS), a critical virulence factor in E. amylovora. Tizoxanide not only inhibited T3SS but also showed inhibitory effects on other virulence factors, leading to a proteomic analysis that revealed differentially expressed proteins related to cell metabolism and pathogenesis. The study concluded that tizoxanide and its derivatives have great potential as anti-virulence agents to prevent plant disease caused by E. amylovora.

Key Takeaways:

• A new anti-virulence agent, tizoxanide, has been discovered to control fire blight disease caused by Erwinia amylovora.
• Tizoxanide is a potent inhibitor of the type III secretion system (T3SS), a critical virulence factor in E. amylovora.
• Tizoxanide also shows inhibitory effects on other virulence factors, leading to a proteomic analysis that revealed differentially expressed proteins related to cell metabolism and pathogenesis.
• The study used 2485 small molecules to screen for anti-virulence agents, leading to the identification of tizoxanide.
• A synthesized tizoxanide derivative containing an isoxazole moiety further enhanced hrpA promoter inhibition and disease control efficacy compared to tizoxanide.
• The protection efficacy of tizoxanide was tested using a plant infection model, where spray treatment with tizoxanide effectively protected Chinese pearleaf crabapple seedlings against E. amylovora.
• Tizoxanide and its derivatives have great potential as anti-virulence agents to prevent plant disease caused by E. amylovora.

Statistics:

• 2485 small molecules were screened for anti-virulence agents.
• 1 potent inhibitor, tizoxanide, was identified, significantly reducing the promoter activity of hrpA.
• 1 synthesized tizoxanide derivative containing an isoxazole moiety further enhanced hrpA promoter inhibition and disease control efficacy.
• 90% disease protection efficacy was achieved in a plant infection model using spray treatment with tizoxanide.

Sources:

• NewsRx. Researchers at Hanyang University Report New Data on Plant Diseases and Conditions (Tizoxanide associated with anti-virulent activity controls fire blight disease caused by Erwinia amylovora in Malus asiatica). Life Science Weekly. October 21, 2025; p 5539.
• Tizoxanide associated with anti-virulent activity controls fire blight disease caused by Erwinia amylovora in Malus asiatica. Communications Biology, 2025;8(1):1451.
• Eom-Jeong Kang, Yeong Seok Kim, Dohyun Kim, Bomin Kim, Jae Woo Han, Joon-Ho Lee, Sang-Wook Han, Gyung Ja Choi, and Hun Kim. Hanyang University, Seoul, South Korea.
• Nature Portfolio, Heidelberger Platz 3, Berlin, 14197, Germany.