T3SS-IN-5 (Compound F9) is a specific inhibitor of the type III secretion system (T3SS), a virulence factor. By suppressing the expression of genes associated with T3SS, T3SS-IN-5 reduces the pathogenicity of bacteria without affecting their viability.

T3SS-IN-5 does not have a statistically significant effect on the survival of Xcc. When used at 200 μM for 5 days, T3SS-IN-5 significantly reduces the hypersensitive response (HR) induced by Xcc-jx-6 in Nicotiana benthamiana. At the same concentration over 4-7 days, it alleviates canker symptoms in Orah orange more effectively than bismerthiazol. Treatment with T3SS-IN-5 at 200 μM for 16 hours significantly lowers the relative incidence of disease caused by Xcc. However, T3SS-IN-5 (200 μM for 48 hours to 5 days) does not affect other virulence factors of Xcc, such as extracellular enzyme activity, EPS activity, motility, and biofilm formation. Additionally, the combination of T3SS-IN-5 (100-200 μM for 4 days) with Burkholderia anthina hN-8 enhances the inhibitory effect on Xcc.