链格孢菌毒素能诱导中国月季产生抗蚜活性的细交链孢菌酮酸（英文）

Alternaria toxin-induced resistance in rose plants against rose aphid(Macrosiphum rosivorum): effect of tenuazonic acid

目的:研究链格孢菌毒素能诱导中国月季植株产生对月季长管蚜的抗性,从而证实寄主植物介导的病虫互作关系的存在,并研究其互作机制。创新点:证实了一种对寄主植物和害虫均无毒性的真菌毒素能使寄主植物产生对昆虫的诱导抗性。方法:马铃薯葡萄糖琼脂(PDA)培养基培养链格孢菌获得毒素粗品,大孔树脂纯化后配制成不同浓度的溶液,喷施到中国月季植株上。处理结束后接种月季长管蚜,与对照相比,计算毒素处理对蚜虫的抑制百分数。用高效液相色谱法(HPLC)结合标准品分析毒素中是否存在细交链孢菌酮酸(TeA),并测定其含量。TeA同法处理中国月季植株,测定TeA对蚜虫的抑制率,并与毒素粗品比较。再通过HPLC法测定植物体表和体内残留的TeA,以证明TeA能自然降解完全。结论:(1)链格孢菌粗毒素和对照品TeA均能使中国月季植株产生对月季长管蚜的系统诱导抗性,显著降低月季长管蚜对中国月季的危害;(2)链格孢菌粗毒素中的主要抗蚜活性成分是TeA,TeA有望成为中国月季上具有抗蚜活性的先导化合物;(3)粗毒素和对照品TeA对蚜虫和植物均无伤害作用,但能激活植物对虫害的诱导抗性(ISR)和系统获得性抗性(SAR),可直接证实二者间存在着寄主植物介导的间接的病虫互作关系。

Many different types of toxins are produced by the fungus, Alternaria alternata （Fr.） Keissler. Little is known, however, regarding the influence of these toxins on insects. In this study, we investigated the toxin-induced inhibitory effects of the toxin produced by A. alternata on the rose aphid, Macrosiphum rosivorum, when the toxin was applied to leaves of the rose, Rosa chinensis. The results demonstrated that the purified crude toxin was non-harmful to rose plants and rose aphids, but had an intensive inhibitory effect on the multiplication of aphids. The inhibitory index against rose aphids reached 87.99% when rose plants were sprayed with the toxin solution at a low concentration. Further results from bioassays with aphids and high performance liquid chromatography （HPLC） analyses demon- strated that tenuazonic acid （TEA） was one of the most important resistance-related active components in the crude toxin. The content of TeA was 0.1199% in the crude toxin under the HPLC method. Similar to the crude toxin, the inhibitory index of pure TeA reached 83.60% 15 d after the rose plants were sprayed with pure TeA solution at the lower concentration of 0.060 IJg/ml, while the contents of residual TeA on the surface and in the inner portion of the rose plants were only 0.04 and 0.00 ng/g fresh weight of TeA-treated rose twigs, respectively, 7 d after the treatment. Our results show that TeA, an active component in the A. alternata toxin, can induce the indirect plant-mediated re- sponses in rose plants to intensively enhance the plant＇s resistances against rose aphids, and the results are very helpful to understand the plant-mediated interaction between fungi and insects on their shared host plants.