噻唑锌对水稻黄单胞杆菌生物学活性初步研究

Preliminary study on biological activity of zinc thiazole against X anthom onas oryzae pv. oryzae

初步研究了噻唑锌在离体条件下对水稻黄单胞杆菌Xanthomonas oryzae pv.oryzae(Xoo)生长的抑制作用,以及其在水稻上防治白叶枯病的生物活性及抗性风险。结果表明,噻唑锌在离体条件下抑制Xoo生长的平均EC50值为(90.17±4.66)μg/mL,且通过紫外光诱导难以获得生长不受影响的抗药性菌株。温室盆栽试验表明,活体条件下噻唑锌对水稻白叶枯病的治疗和保护作用EC50值分别为22.90和52.38μg/mL,其治疗作用显著优于保护作用。从药剂处理稻苗后接种Xoo所形成的病斑上,能够筛选到致病力不受影响的Xoo抗药性突变体,其突变频率为13.3%。交互抗性研究表明,噻唑锌与噻枯唑之间存在交互抗性,但抗药性性状不能稳定遗传。内吸传导性研究表明,噻唑锌能被水稻根部和叶片吸收,且表现为向上传导性。噻唑锌对Xoo的活体抑制活性高于其离体活性,且抗性风险低,适用于防治水稻白叶枯病。

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 ECs0 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 ECs0 values were 22.90 and 52.38 μg/mL for 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 l0 transfers on zinc thiazole-free medium subcultures. In addition, zinc thiazole could be absorbed by roots and leaves of rice and exhibited upward movementcharacteristics 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.