烟草花叶病毒病是危害烟草的重要病害,可通过激发子诱导烟草产生抗病性.利用乙醇沉淀、DEAE-52、SephadexG-100柱层析的方法,从疫霉菌中分离纯化出一种葡聚糖类激发子Gep1.Gep1诱导后,烟草叶片产生和积累H2O2、酚类物质;烟草叶片苯丙氨酸解氨酶、多酚氧化酶和过氧化物酶活性均有不同程度的提高.Gep1可以诱导烟草抗TMV.盆栽实验表明,4 mg/mL Gep1的防效为67.4%,降低了发病率,推迟了发病时间.半定量RT-PCR结果显示,Gep1激发子诱导烟草抗病相关基因的上调表达,表明Gep1可激发烟草防卫反应,诱导烟草产生系统抗性,提高烟草对病毒的抗性.%Tobacco mosaic virus is an important disease and causes damage on tobacco. Elicitors can induce tobacco systemic resistance against TMV. In this study, a glucan elicitor Gep1 was isolated and purified from the culture filtrate of Phytophthorasp. through the procedures of ethanol precipitation, DEAE-52 and SephadexG-100 column chromatography. Gep1 triggered tobacco defense responses. After induced by Gep1, H2O2 and phenolics accumulated more and activities of peroxides, polypheol oxidase and phenylalanine ammonia lyase all increased in tobacco leaves. Gep1 could induce tobacco resistance against TMV. In pot experiment, control efficiency of 4 mg/mL Gep1 was 67.4%. Gep1 could effectively reduce the incidence and delay the onset time. Semi-quantitative RT-PCR data revealed that expression of the resistance-related genes in tobacco was up-regulated after Gep1 treatment. The results suggested that Gep1 could trigger defense reactions, induce systemic resistance and improve resistance of tobacco against TMV.
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