SGER: Sensory Transduction of Blue Light in Corn coleoptiles

该提案要求获得探索性研究的小额赠款， 开发初步数据，对假设进行关键检验， 类胡萝卜素作为蓝光光感受器， 玉米胚芽鞘的向光反应 目前的想法， 该领域将蓝光感光器的作用归因于黄素或 黄素蛋白 然而，该实验室最近的工作 为类胡萝卜素的作用提供了诱人的证据， 玉米黄质在蓝光光感受中的作用。 研究提出， 这里讨论的问题是，这种分子是否作为 胚芽鞘向光性的光感受器， 蓝光反应 对玉米胚芽鞘的初步研究 表明它们运行叶黄素循环， 追踪其光环境的浓度。 提出 设计实验来关联向光性的程度 玉米黄质浓度的反应 胚芽鞘，并确定胚芽鞘叶绿体是否显示 蓝光反应。 其他玉米突变体的实验， 改变的颜料组合物将试图将 向光敏感性与其色素含量有关。 中蓝光传感机制的表征 胚芽鞘系统将大大提高我们对 植物的蓝光感觉传导。 %%% 植物对环境最基本的反应之一 是一株幼苗的生长尖端转动并生长 走向光明 蓝光是最有效的引发这种 反应，但植物尖端感知蓝光的机制是 还不明白。 作为响应蓝光的第一步 必须被一种特定的化合物吸收，但这种化学物质 光感受器尚未确定。 确定蓝光感光器的性质将是一个重要的研究方向。 对了解这种基本植物的重要贡献 反应 间接证据使大多数调查人员 这个领域相信感光器可能是一种 一种被称为“黄素”的有机分子。 然而，Zeiger博士 得到的一些结果表明，不同类别的有机 分子，“类胡萝卜素”可能是真实的蓝光受体。如果 类胡萝卜素确实是蓝光受体， 这是一个非常重要的进步，但目前的证据也是如此。 不足以证明启动全面研究计划的合理性， 个话题吧 这项探索性研究的小额赠款将允许 Zeiger博士开发足够的初步数据来确定 应否进行全面的研究计划， 类胡萝卜素作为蓝光光感受器的功能。

This proposal requests a Small Grant for Exploratory Research to develop preliminary data for a critical test of the hypothesis that carotenoids function as blue light photoreceptors in the phototropic response of corn coleoptiles. Current thinking in the field ascribes the role of blue light photoreceptor to flavins or flavoproteins. Recent work in this laboratory, however, has provided tantalizing evidence for a role of the carotenoid, zeaxanthin in blue light photoreception. The research proposed here addresses the question of whether this molecule serves as the photoreceptor for coleoptile phototropism, a well characterized blue light response. Pilot studies with corn coleoptiles have shown that they operate the xanthophyll cycle and have zeanthin concentrations that track their light environment. Proposed experiments are designed to correlate the extent of the phototropic response with prevailing zeaxanthin concentrations in the coleoptile, and to establish whether coleoptile chloroplasts show a blue light response. Other experiments with corn mutants having an altered pigment composition will seek to correlate changes in phototropic sensitivity with their pigment content. Characterization of the blue light sensing mechanism in the coleoptile system would significantly enhance our understanding of blue light sensory transduction in plants. %%% One of the most fundamental responses of a plant to its environment is that the growing tip of a young plant shoot turns and grows toward light. Blue light is most effective in eliciting this response, but the mechanism by which plant tips sense blue light is not yet understood. As the first step in the response blue light must be absorbed by a specific chemical compound, but the chemical photoreceptor has not yet been identified with certainty. Establishing the nature of the blue light photoreceptor would be an important contribution to understanding of this fundamental plant response. Circumstantial evidence has led most investigators in the field to believe that the photoreceptor is probably a type of organic molecule known as a "flavin". Dr. Zeiger, however, has obtained some results suggesting that a different class of organic molecule, a "carotenoid" may be the real blue light receptor. If a carotenoid is, indeed, the blue light photoreceptor this would be a very important advance, but the evidence at present is too incomplete to justify launching a full scale research program on the subject. This Small Grant for Exploratory Research will permit Dr. Zeiger to develop sufficient preliminary data to determine whether a full scale project should be undertaken to study the function of carotenoids as blue light photoreceptors.