The Role of Terpene Synthases in Floral Scent Emission in Arabidopsis thaliana and Related Species

拟南芥是最重要的植物模式生物，其全部基因的序列已为人们所知。虽然人们普遍认为柳杉的花大多是自花授粉的，但我们发现这种花释放出萜类化合物的气味挥发物，以前的报告确实表明，自然界中确实发生了水平不明的异花授粉。拟南芥基因组有33个与已知萜烯合成酶(TPSS)同源的基因，我们已经证明，在正常条件下，其中5个基因仅在花中表达，另外14个基因在花中以及其他一些组织中表达。在这个项目中，Pichersky博士的实验室将表征来自不同环境的刺参植物的花香，表征由所有花表达的TPS基因编码的酶的活性，对这些TPS基因在整个植物中的组织特异性表达进行详细检查，识别访花昆虫，并估计由这种访花引起的异花授粉水平。气味更明显的近缘物种也将被比较。该项目是对花香的生物合成及其对异花授粉成功的影响的跨学科研究，包括从分子生物学到生物化学再到生态学的方法。这些结果将提供对迄今为止鲜为人知的一种重要植物生命特征的详细了解。这一新知识也将高度适用于农作物，其中许多作物依赖于种子和果实的异花授粉。了解气味基因是如何在A.thaliana模式系统中被激活的，将有助于在重要的农作物中发现和操纵气味基因，以提高气味产生并吸引有益的传粉者。最后，该项目将在国际和平研究所的实验室和正规课程中为研究生和本科生提供出色的跨学科培训和教育，国际和平研究所除了在科学期刊上发表报告外，还将继续向公众传播结果。

Arabidopsis thaliana is the most important plant model organism, and the sequence of its entire complement of genes is now known. Although it is generally believed that A. thaliana flowers mostly self-pollinate, we have discovered that the flowers emit scent volatiles of the terpene class of compounds, and previous reports do suggest that an undetermined level of cross-pollination does occur in nature. The A. thaliana genome has 33 genes with homology to known terpene synthases (TPSs), and we have shown that under normal conditions, five of these genes are expressed exclusively in flowers, and 14 more are expressed in flowers as well as in some other tissues. In this project, Dr. Pichersky's lab will characterize the floral scent of A. thaliana plants from different environments, characterize the activity of the enzymes encoded by all the flower-expressed TPS genes, perform a detailed examination of the tissue-specific expression of these TPS genes throughout the plant, identify insect visitors to A. thaliana flowers, and estimate the level of cross-pollination caused by such visits. Related species that are more noticeably scented will also be compared. This project is an interdisciplinary investigation of the biosynthesis of floral scent and its effect on the success of cross-pollination, encompassing methods from molecular biology to biochemistry to ecology. The results will provide detailed understanding of an important plant life trait that has hitherto been little understood. This new knowledge will also be highly applicable to crop plants, many of which depend on cross-pollination for seed and fruit set. Knowing how scent genes are activated in the A. thaliana model system will facilitate the discovery and manipulation of scent genes in important crop plants to enhance scent production and attract beneficial pollinators. Finally, the project will provide excellent interdisciplinary training and education for graduate and undergraduate students both in the PI's lab and in formal courses, and the PI will continue to disseminate the results to the general public in addition to reports in scientific journals.