Identification of candidate genes responsible for preformed and inducible defence response in oaks against herbivorous insects

橡树落叶是中欧林业面临的一个紧迫问题。在2003-2005年的上一次橡树卷叶蛾暴发期间，我们观察到德国栎树个体落叶水平的根本差异。有些树似乎对昆虫幼虫有某种程度的“耐受性”(T橡树)，而有些树似乎明显地“敏感”(S橡树)。在这项研究中，我们的目标是确定在橡树中潜在的分子和生化机制，负责卷蛾的行为偏好。通过联合取食选择实验和对T和S栎树表型预制和诱导防御机制的生化分析，我们将确定观察到的差异的代谢/化学基础，作为筛选在耐性树中表达的候选基因的先决条件，而不是在昆虫取食后在敏感树中表达的候选基因或在敏感树中表达的候选基因。我们将在北莱茵-威斯特伐利亚(西德)的一个研究区通过微阵列分析已经确定的T和S橡树表型，鉴定与橡树(Q.robur)树防御反应(即酚类化合物和植物挥发物)相关的功能基因。这一方法将使我们深入了解与食草性昆虫食性有关的罗布泊功能基因组学。通过分子和生化标记的鉴定，我们可以为可持续森林经营提供决策支持。

The defoliation of oaks is an urgent problem for forestry in Central Europe. During the last outbreak of the green oak leaf roller (Tortrix viridana) in 2003-2005, we observed fundamental differences in the defoliation level of individual Quercus robur trees in Germany. Some of the trees seem to be somehow “tolerant” (T oaks) against the insects grub while some seem to be conspicuously “susceptible” (S oaks). Within this study we aim to identify the underlying molecular and biochemical mechanisms in oaks responsible for the behavioural preference of Tortrix viridana. By means of combined feeding choice experiments and biochemical analysis of preformed and induced defence mechanisms in T and S oak phenotypes, we will identify the metabolic/chemical basis of the observed differences as prerequisite for the selection of candidate genes expressed in tolerant trees, but not in susceptible ones or vice versa after insects feeding. We will identify functional genes involved in the defence response (i.e. phenolic compounds and plant volatiles) of oak (Q. robur) trees via microarray analysis in already identified T and S oak phenotypes in a research area in North Rhine-Westphalia (Western Germany). This approach will give us a deep insight into the functional genomics of Q. robur relating to the feeding of herbivorous insects. With the identification of molecular and biochemical markers of “Tortrix tolerance” in oaks we can contribute to decision support in sustainable forest management.