Cui Hongying, Wei Jianing, Su Jianwei, Li Chuanyou, Ge Feng
State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, PR China; Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China.
State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, PR China.
Plant Sci. 2016 Dec;253:243-250. doi: 10.1016/j.plantsci.2016.09.019. Epub 2016 Oct 6.
The elevated atmospheric O level may change the interactions of plants and insects, which potentially affects direct and indirect plant defences. However, the underlying mechanism of the impact of elevated O on indirect plant defence, namely the efficacy of natural enemies, is unclear. Here we tested a hypothesis that linked the effects of elevated O and whitefly herbivory on tomato volatile releases mediated by the jasmonic acid (JA) pathway with the preferences of parasitoid Encarsia formosa for two different tomato genotypes (wild-type (Wt) and JA-deficient genotype (spr2)). The O and whitefly herbivory significantly increased the production of volatile organic compounds (VOCs), including monoterpenes and green leaf volatiles (GLVs). The Wt plants released higher volatile levels, particularly monoterpenes, than did the spr2 plants. In Y-tube tests, limonene and Z-3-hexanol played key roles in the attraction of E. formosa. Moreover, regardless of plant genotype, the two plant genotypes were preferred by adult E. formosa under the O and O+ herbivory treatments. Our results suggest that under elevated O, the activation of the JA pathway significantly up-regulates the emission rates of volatiles, through which the efficacy of natural enemy might be promoted.
大气中氧气水平升高可能会改变植物与昆虫之间的相互作用，这可能会影响植物的直接防御和间接防御。然而，氧气水平升高对植物间接防御（即天敌的效能）影响的潜在机制尚不清楚。在此，我们测试了一个假设，即氧气水平升高和粉虱取食对由茉莉酸（JA）途径介导的番茄挥发性物质释放的影响，与寄生蜂丽蚜小蜂对两种不同番茄基因型（野生型（Wt）和JA缺陷型基因型（spr2））的偏好有关。氧气水平和粉虱取食显著增加了挥发性有机化合物（VOCs）的产生，包括单萜和绿叶挥发物（GLVs）。Wt植株比spr2植株释放出更高水平的挥发物，尤其是单萜。在Y型管试验中，柠檬烯和Z-3-己醇在吸引丽蚜小蜂方面起关键作用。此外，无论植物基因型如何，在氧气水平升高和氧气水平升高+粉虱取食处理下，两种植物基因型均受到丽蚜小蜂成虫的偏好。我们的结果表明，在氧气水平升高的情况下，JA途径的激活显著上调了挥发物的释放速率，通过这种方式可能会提高天敌的效能。
