イネにおけるエリシター化合物を利用した天敵誘引物質の放出制御技術の開発

在2007财年，我们继续测量水稻（Oryza sativa）和高粱（sorghum bicolor）的挥发性有机化合物（VOC）排放量。在这两种植物中，我们测定了以萜类化合物、芳香族化合物和绿叶挥发物为主的全谱挥发性有机化合物。在这两种单子叶植物中，挥发性有机化合物非常相似，以倍半萜类和单萜类为主。草食动物取食和昼夜条件是影响挥发性有机化合物排放的主要因素，化学诱导剂（BTH）和植物基因型对挥发性有机化合物排放有进一步的影响。为了了解单子叶植物在控制和胁迫条件下（草食和伤害）挥发性有机化合物差异排放的分子基础，我们克隆并研究了直接参与挥发性有机化合物生物合成的基因表达。为了将VOCs差异与植物对昆虫的间接防御联系起来，我们还对不同遗传背景（导致VOCs差异）的高粱植物进行了监测，并在田间条件下研究了它们的草食伤害。虽然二者之间的直接关系还有待建立，但与易感NOG基因型相比，VOCs排放量较高的BTx602源高粱在田间受到欧洲茎螟虫（Ostrinia nubilalis）的危害较低（高危害vs低VOCs）。我们可以提出这样的假设：BTx602的高挥发性有机化合物含量可能有助于这些植物吸收更多的白僵虫天敌，从而减少白僵虫在这些植物上的成功建立。目前正在编写几份总结我们研究结果的出版物。

In FY 27, we continued measuring volatile organic compound (VOC) emissions from rice (Oryza sativa) and sorghum (Sorghum bicolor). In both plants, we determined whole spectrum of VOCs dominated by terpenoids, aromatic compounds and green leaf volatiles. In both monocot species, the VOCs were quite similar, dominated by sesquiterpenes and monoterpens. Herbivore feeding and diurnal conditions were main factors influencing VOC emissions, which was further affected by chemical inducers (BTH) and plant genotype. In order to understand the molecular basis of differential emissions of VOCs from monocot plants, both under control and stress conditions (herbivory, wounding), we initiated cloning and investigated gene expression of those genes directly involved in VOC biosynthesis. In order to correlate differential VOCs with plant indirect defense against insects, we also monitored sorghum plants of different genetic backgrounds (resulting in differential VOCs), and investigated their herbivore damage under field conditions. Although direct relationship still needs to be established, sorghum plants of BTx602 origin, which had higher emissions of VOCs, had lower damage from European stem borer (Ostrinia nubilalis) in the field, compared to susceptible NOG genotype (high damage vs. low VOCs). We could propose hypothesis that high VOCs in BTx602 may help these plants to recruit a higher number of natural enemies of O. nubilalis, and thus reduce the successful establishment of this notorious pest on these plants. Several publications summarizing our results are now under preparation.