嘧菌酯对油菜菌核病菌的抗菌活性及抗菌机制研究

测定了嘧菌酯对油菜菌核病菌Sclerotinia sclerotiorum菌丝生长、菌核产生和菌丝呼吸作用的影响。结果表明,嘧菌酯对油菜菌核病菌菌丝生长具有明显的抑制作用,且药剂处理浓度在1.0 μg/mL 时能显著抑制其菌核产量。旁路氧化酶专化抑制剂水杨肟酸(SHAM)对嘧菌酯的抗菌活性有显著的协同作用,协同增效系数达到3.27~14.13倍。药剂处理后48 h内,嘧菌酯抑制菌丝生长的剂量曲线与抑制菌丝呼吸的耗氧速率曲线趋势相似;48 h以后,单位质量菌丝耗氧速率上升,且高于空白对照,而菌丝的生长量并没有增加,表明菌丝体正常呼吸作用受嘧菌酯抑制48 h 后会发生耗氧增强的生理应急反应。水杨肟酸在嘧菌酯处理后1 h内对菌丝呼吸没有抑制作用,但在嘧菌酯处理1 h后对菌丝呼吸表现为抑制作用,表明油菜菌核病菌菌丝在以细胞色素为载体的呼吸链的电子传递受到嘧菌酯阻断后,可以诱导耗氧更高的旁路氧化途径。

Study on Fungicidal Activity and Mechanism of Azoxystrobinagainst Sclerotinia sclerotiorum

The activity of azoxystrobin inhibiting mycelial growth of Sclerotinia sclerotiorum was tested by mycelial growth rate method and the effect of azoxystrobin on the sclerotinia yield and respiration in mycelial growth of S.sclerotiorum was assessed.The results showed that azoxystrobin strongly inhibited the mycelial growth,and 1.0 μg/mL azoxystrobin could inhibit sclerotinia production obviously.Synergistic interaction against S.sclerotiorum existed between salicylhydroxamic acid (SHAM),a specific inhibitor of alternative oxidase,and azoxystrobin.The synergistic ratio ranges from 3.27 to 14.13.The dose-response curves of azoxystrobin inhibiting mycelial growth were almost parallel to that of oxygen consumption rate of the fungus within 48 h.However,higher oxygen consumption rate in mycelia than the untreated was found 48 hours after treated with azoxytrobin,and the mycelial growth did not increase.It suggested that some urgent reaction of mycelia occurred in response to the inhibition of azoxystrobin in S.sclerotiorum after 48 h.SHAM did not show the inhibitory activity against the mycelial respiration of S.sclerotiorum within 1 h until the mycelia was treated with azoxystrobin after 1 h,indicating that the alternative oxidase pathway could be induced when mitochondrial electron transferring in cyt bc1 complex was prevented by azoxystrobin.