Preliminary study on biological activity of zinc thiazole against Xanthomonas oryzae pv.oryzae

The toxicity in vitro, the biological activity and the resistance risk of zinc thiazole in vivo against Xanthomonas oryzae pv.oryzae(Xoo) were preliminarily studied. The results showed that the EC50 value of zinc thiazole to the bacteria in vitro was (90.17±4.66) μg/mL, and repeated ultraviolet light induction can could not acquire resistant strain. Protective and curative effect of zinc thiazole against bacterial leaf blight of rice was assayed in vivo, and the EC50 values were 22.90 and 52.38 μg/mLfor curative and protective activity, respectively, suggesting the curative activity of zinc thiazole was better than that of protective activity. Resistant mutants of Xoo were detected by screening with zinc thiazole in vivo, and the resistance mutant frequency was 13.3%. There was positive cross-resistance between zinc thiazole and bismerthiazol in Xoo. However, the resistance of these mutants was relatively low and not stable after 10 transfers on zinc thiazole-free medium subcultures. In addition, zinc thiazole could be absorbed by roots and leaves of rice and exhibited upward movement characteristics from the application site. In conclusion, the inhibitory activity to Xoo of zinc thiazole is better than that of growth activity. Zinc thiazole can be used for controlling Xoo with a low resistance risk.