Induction of plant volatiles by insect egg deposition on elm (Ulmus campestris): using molecular methods and genetic transformation to understand an ecological phenomenon

众所周知，许多植物对食草动物的取食反应是通过释放挥发性化合物来吸引食草动物的敌人。然而，关于这些间接防御的诱导、调节、特异性和自然功能仍有许多悬而未决的问题。我们最近已经证明，欧洲田间榆树(Ulmus Campestris)在真正的草食开始之前，即榆叶甲虫(Xanthoglaruca Luteola)产卵之后，就会释放挥发性物质作为对昆虫食草动物的反应。落卵附近的叶子释放出以萜类挥发物为主的特定混合物，对卵寄生蜂Omyzus Gallerucae具有很强的诱惑力。本研究综合运用化学生态学、分析化学、分子生物学和植物转化等多种方法，研究了油菜挥发性物质在基因表达水平的诱导方式，油菜是如何在特定的时间和空间尺度上调节诱导的挥发物产生的，以及(C)与寄生相关的基因在诱集寄生过程中的作用。

It has been known for some years that many plants respond to herbivore feeding by releasing volatile compounds which attract enemies of the herbivores. However, there are many unanswered questions regarding the induction, regulation, specificity, and natural function of these indirect defences. We have shown recently that the European field elm (Ulmus campestris) releases volatiles in response to insect herbivores before actual herbivory has even begun, namely after egg deposition by elm leaf beetles (Xanthogaleruca luteola). Leaves in the vicinity of the deposited eggs release specific blends of mostly terpenoid volatiles, which are highly attractive to the egg parasitoid Oomyzus gallerucae. By combining methods from chemical ecology, analytical chemistry, molecular biology and plant transformation, we intend to investigate (a) the mode of volatile induction at the level of gene expression, (b) how U. campestris regulated the production of the induced volatiles on specific temporal and spatial scales, and (c) the function of the genes associated with the volatiles involved in parasitoid attraction, through the use of genetically-transformed lines of U. campestris which will be tested with the egg parasitoids in olfactometer bioassays.