雷帕霉素对4种植物病原真菌的抑菌活性

采用菌丝生长速率法,测定了雷帕霉素对番茄灰霉病菌、油菜菌核病菌、水稻纹枯病菌和棉花枯萎病菌的抑菌活性,比较了嘧菌酯、丙烷脒及雷帕霉素对番茄灰霉病菌的抑菌效果,并通过电子显微镜观察了雷帕霉素对番茄灰霉病菌菌丝生长的影响。结果表明:雷帕霉素对供试4种植物病原真菌菌丝均表现出了极强的抑制活性,其中对油菜菌核病菌的抑制作用最强,EC50值为2.23×10-4μg/mL,对番茄灰霉病菌、水稻纹枯病菌和棉花枯萎病菌的EC50值分别为1.32×10-3、4.05×10-3及3.82×10-3μg/mL;雷帕霉素对番茄灰霉病菌菌丝的抑制活性显著高于嘧菌酯(EC50值为3.24μg/mL)和丙烷脒(EC50值为3.81μg/mL)。电镜观察发现,经雷帕霉素处理后,番茄灰霉病菌菌丝表现出提前衰老等症状。研究结果可为深入探讨雷帕霉素对植物病原真菌的作用机制奠定基础。

Antifungal activity of rapamycin against four kinds of plant pathogenic fungi

Rapamycin is an important marocyclic polyketide produced by Streptomyces hygroscopicus, which exhibited immunosuppressive and antifungal properties. In this study, antifungal activity of rapamycin against four kinds of plant pathogens, including Botrytis cinerea, Sclerotinia sclerotiorum, Rhizoctonia solani, and Fusarium oxysporum, was assayed by the mycelium growth rate method. The results showed that rapamycin exhibited extreme significant inhibit efficacy against mycelial growth of all of these plant pahogens on the PDA medium. The EC50 value of rapamycin against S. sclerotiorum was 2.23 × 10–4 μg/mL, which is the lowest. The EC50 values against B. cinerea, R. solani, and F. oxysporum were 1.32 × 10–3, 4.05 × 10–3 and 3.82 × 10–3 μg/mL, respectively. It is noteworthy that the toxicity of rapamycin against the mycelial growth of B. cinerea is significantly higher than those of azoxystrobin and propamidine, with the EC50 values of 3.24 and 3.81 μg/mL, respectively. The hypha of B. cinerea exhibited premature aging after treated with rapamycin under the scanning electron microscope. The results in this study provided the basis for investigating the efficient inhibitation mechanism of rapamycin in the future study.