Molecular Genetics of Flower Scents

9417582 Pichersky花的气味对植物繁殖成功有很大的影响，因此是水果作物产量的关键决定因素，需要寻找气味的授粉者。 然而，花香味物质的生物合成途径却很少在生化、遗传和分子水平上得到研究。 皮彻斯基博士打算研究Clarkia的气味产生，Clarkia是一种原产于加州的一年生植物。 Clarkia breweri是该属中唯一具有花香的物种;其花主要由天蛾访问。 无臭花C. concinna，与C. breweri出现，主要由蝴蝶访问，而所有其他异交的Clarkia物种都由蜜蜂授粉。 研究人员已经确定了两个主要的途径，有助于花卉气味的C。 breweri。这些途径之一，这个propoal的主题，在单萜芳樟醇和芳樟醇氧化物的生产结果。 研究表明，这一通路在C.因此，看来，在一个大大降低的水平，在C。breweri通过上调该途径而发生。 为了验证这一假设，Pichersky博士和他的同事们已经开发了一种芳樟醇合成酶（LIS）的酶测定法，这种酶催化芳樟醇的形成，并纯化了蛋白质。 他们现在将开发一种分光光度法测定芳樟醇环氧（LIE），这种酶催化形成6，7-芳樟醇环氧，这是芳樟醇氧化物形成的中间体。 他们将从两种Clarkia物种中分离和表征Lis和Lie基因，并使用重组启动子-GUS报告基因融合和植物转化以及DNA-蛋白质相互作用测定来研究控制其表达并负责种间差异的遗传和分子控制机制。 将使用免疫学技术的组合来确定酶的细胞和细胞下定位。 所获得的数据将增加我们对花香产生的生化和遗传控制的理解，并可能导致未来在农艺学上重要的植物中操纵这些性状的能力。

9417582 Pichersky Flower scents exert strong influence on plant reproductive success, and thus are crucial determinants of yield in fruit crops that require scent-seeking pollinators. However, the biosynthetic pathways of floral scents have scarcely been investigated on the biochemical, genetic and molecular levels. Dr. Pichersky proposes to study scent production in Clarkia, a genus of annual plants native to California. Clarkia breweri is the only species in the genus with floral scent; its flowers are visited mostly by hawkmoths. The odorless flowers of C. concinna, a closely related species from which C. breweri arose, are visited mostly by butterflies, whereas all other outcrossing Clarkia species are pollinated by bees. The investigator has identified two major pathways that contribute to the floral scent of C. breweri. One of these pathways, the subject of this propoal, results in the production of the monoterpenes linalool and linalool oxides. It has been shown that this pathway also operates in C. Concinna flowers as well, albeit at a greatly reduced level, and it therefore appears that the evolution of monoterpene emission in C. breweri has occurrred by up- regulating this pathway. To test this hypothesis, Dr. Pichersky and his colleagues have already developed an enzymatic assay for linalool synthase (LIS), the enzyme that catalyzes the formation of linalool, and have purified the protein. They will now develop a spectrophotometric assay for linalool epoxidae (LIE), the enzyme that catalyzes the formation of 6,7-linalool expoxide, an intermediate in the formation of linalool oxides. They will isolate and characterize the Lis and Lie genes from both Clarkia species and investigate the genetic and molecular control mechanisms that govern their expression and are responsible for the interspecific differences, using recombinant promoter - GUS reporter gene fusion and plant transforation and DNA-protein interaction assays. The cellular and subce llular localization of the enzymes will be determined using a combination of immunological techniques. The data obtained will increase our understanding of the biochemical and genetic control of flower scent production, and may lead to future ability to manipulate these traits in agronomically important plants.