【作者】 杨丽梅；

【导师】 方智远；

【作者基本信息】 中国农业科学院 ， 蔬菜学， 2008， 博士

【摘要】 寄主植物抗性和生物防治是两种主要的可持续的害虫防治方法。这些方法通常是独立发展的。然而寄主植物的特征能够显著地影响生物防治的效力,因此当在一个育种程序中改变了植物的特性时,其对生物防治的意义也应被加以研究。此外,这也可以为选育与生物防治极好兼容的植物提供机会。以寄主植物抗性为目标的育种有着悠久的历史。然而在过去数十年中一个新的发展就是利用转基因技术产生抗虫抗病的植物。在最近几年,植物基因工程使得外源基因转入寄主植物成为可能,使它具有抗虫性或使寄主植物产生遭到植食性昆虫攻击后可以吸引害虫天敌的挥发物。在本论文中通过转基因方法改进了拟南芥植物对植食性昆虫的直接和间接防御,旨在评价带有不同基因的转基因拟南芥对植食性昆虫小菜蛾直接防御和间接防御的影响。来自芥菜的蛋白酶抑制剂(芥菜胰蛋白酶抑制剂2,MTI2)被用于对小菜蛾(Plutella xylostella)影响的研究,MTI2转基因拟南芥不影响小菜蛾的荷兰种群和中国种群的表现。我们的数据表明,小菜蛾的肠道酶对MTI2是不敏感的,这可以被解释为MTI2的特定失活。很显然,小菜蛾通过使MTI2失活来保护自己免受这种蛋白酶抑制剂的作用。而这具有生态学意义,因为MTI2是其芸薹属寄主植物防御的组成部分。萜类化合物是参与许多植物间接防卫的植物挥发物的一种。本研究开发了芳樟醇合酶基因在害虫诱导产生转基因拟南芥植物中的可用性,并且创造了由来自马铃薯蛋白酶抑制剂2启动子PI2控制的LIS基因的转基因拟南芥。结果显示芳樟醇合成酶可以被茉莉酮酸甲酯的应用所诱导,但不能被小菜蛾侵害所诱导。为研究一种利用转基因方法综合植物的直接防御和间接防御,一个编码产生Bt毒素的基因和一个编码产生芳樟醇合酶的基因被整合到拟南芥中作为模型。数据显示,在拟南芥中携带Bt和LIS基因的杂交系结合了对小菜蛾幼虫的毒性(由于Bt)和对小菜蛾成虫的排斥性(由于LIS)。此外当植物受到伤害时,芳樟醇的释放也会影响寄生蜂的行为。被小菜蛾侵害的双转基因植物比完好无损的双转基因植物对半闭弯尾姬蜂(Diadegma semiclausum)的吸引力更强,但是比受小菜蛾侵害的非转基因植物吸引力要弱。寄生蜂对转基因植物上饲喂的小菜蛾幼虫寄生率的百分比不受转基因的影响。总之,本论文的数据提供了对发展转基因作物的令人感兴趣的可能性,它在干扰了害虫生物学的同时增强了害虫天敌的效力。以这种方式可以发展综合寄主植物抗性和生物防治的转基因作物。更多还原

【Abstract】 Two main methods in sustainable pest control are host plant resistance and biological control. These methods have been developed in isolation. However, host plant characteristics can decisively affect the effectiveness of biological control agents, and therefore when altering plant characteristics in a breeding programme, the implications for biological control should be studied as well. Moreover, this may also provide the opportunity to breed for plants that are optimally compatible with biological control agents.Breeding for host plant resistance has a long history. However, in the past decades a new development was to use transgenes to generate plants resistant to pests and diseases. In more recent years also Plant genetic engineering makes it possible to transfer a foreign gene to a host plant to introduce resistance against insects or to produce a volatile which can attract the natural enemy of the pest after the host plant is wounded by insect herbivores. In this thesis I have modified direct and indirect defence to herbivores in Arabidopsis plants through a transgenic approach. In order to evaluate transgenic Arabidopsis with different genes that influence direct and indirect defence to the herbivore Plutella xylostella (diamondback moth, DBM).I investigated the effect of a protease inhibitor from mustard plants (Mustard Trypsin Inhibitor 2, MTI2). MTI-2 transgenic Arabidopsis did not affect the performance of a Dutch and a Chinese strain of DBM. My data show that the gut enzymes of DBM are insensitive to MTI2, which can be explained by the specific inactivation of MTI2. DBM has apparently developed MTI2 inactivation as a way to protect itself against this protease inhibitor. This makes ecological sense as MTI2 is part of the defense of its brassicaceous host plants.Terpenoids are among the plant volatiles involved in indirect defence of many plant species. I exploited the availability of a linalool synthase (LIS) gene to develop transgenic herbivore-inducible linalool-producing Arabidopsis plants and developed Arabidopsis plants with this linalool synthase gene under the protease inhibitor 2 (PI2) promoter from potato. As a result the linalool synthase was inducible by methyl jasmonate application, but not by P. xylostella infestation.To investigate a transgenic approach to combining direct and indirect defence, a gene encoding a Bt toxin and a gene encoding linalool synthase were integrated into Arabidopsis as a model. The data show that hybrid lines carrying Bt and LIS genes in Arabidopsis combine toxicity to the DBM larvae (due to Bt) and repellence to the adults of DBM (due to linalool). Moreover, the linalool emission also affected parasitoid behaviour when the plants were damaged. DBM-infested dual transgenic plants were more attractive to the parasitoid D. semiclausum than undamaged dual transgenic plants, but less attractive than DBM-infested untransformed plants. The percentage parasitization of DBM larvae on transgenic plants was not affected by the transgenes.In conclusion, my data provide interesting options for the development of transgenic crops that interfere with the biology of pests and enhance the effectiveness of the pest’s natural enemies. In this way transgenic crops that integrate host plant resistance with biological control may be developed.更多还原