Chemical and genetic dissection of ABA receptor function

干旱是美国农作物损失的最大原因，迫切需要对抗其影响的战略。为了提高作物的耐旱性，我们必须了解非驯化植物自然抗旱的方式。植物对干旱的反应是产生一种叫做脱落酸（ABA）的化学信号；它的生产将有关干旱的信息从植物的一个部分传递到另一个部分，并确保发生保护性反应。ABA在一种叫做受体的特殊蛋白质的帮助下传递信息，这种蛋白质就像开关一样开启保护性反应。由于未知的原因，植物有异常多的这种开关。研究人员假设，特定类型的开关对干旱反应比其他类型的开关更重要。通过阐明植物细胞的内部工作原理，回答这一假设将具有广泛的智力价值。此外，它还将产生更广泛的重要影响，因为它将有助于培育新的抗旱作物。这名研究人员将在一定程度上使用在以前的NSF资助下开发的合成化学品来测试假设。这些令人兴奋的新化学品使PI实验室和工业科学家之间建立了合作伙伴关系，他们寻求开发能够减轻干旱对作物产量影响的化学品。目前的提案将描述新化学品的特征，并加强学术界与工业界的关系。这个跨学科项目将加强PI对学生和博士后学者的指导，并为植物生物学、遗传学和化学提供独特的培训环境。该研究人员在了解ABA受体的功能和开发合成ABA模拟化合物方面做出了重要贡献。尽管取得了巨大的进展，但我们目前对ABA受体功能的理解受到遗传冗余的阻碍。这个提议提出了一个简单的问题：为什么植物需要这么多的ABA受体？在本提案中，PI将定义哪些受体在调节水关系中起主导作用，并系统地分析不同受体在介导ABA浓度依赖效应中的作用。为此，PI将采用一系列互补的化学、遗传和合成生物学方法。在一种实验方法中，人工合成的小分子可以激活高亲和受体或低亲和受体，用于询问不同受体在不同ABA反应中的作用。小分子是生物途径的强大探针，但可能受到“脱靶”效应的限制，这会使数据的解释复杂化。为了解决这一限制，PI还将使用合成生物学策略和工程受体，这些受体可以被非天然化学物质选择性地控制。结构不相关的分子具有相同脱靶效应的可能性很低，因此这种策略是对第一种策略的补充。最后，基因组编辑将与经典的遗传方法相结合，以产生缺乏不同受体亚型的植物。这些材料将与其他材料一起进行表征，以建立对ABA受体家族功能的综合和系统的理解。

Drought is the largest cause of crop losses in the United States and strategies to combat its effects are urgently needed. In order to improve drought tolerance in crops, we must understand the ways that non-domesticated plants naturally withstand drought. Plants respond to drought by producing a chemical signal called abscisic acid (ABA); its production relays information about drought from one part of the plant to another and ensures that protective responses occur. ABA gets its message across with the help of special proteins called receptors, which act like switches to turn on protective responses. For unknown reasons, plants have an unusually large number of these switches. The researcher hypothesizes that specific types of switches are more important for drought responses than others. Answering this hypothesis will have broad intellectual merit by illuminating the inner workings of plant cells. In addition, it will have important broader impacts, as it will help in breeding new drought tolerant crops. The researcher will test hypotheses, in part, using synthetic chemicals developed under previous NSF funding. These exciting new chemicals have enabled a partnership between the PI's lab and industry scientists, who seek develop chemicals that to mitigate the effects of drought on crop yield. The current proposal will characterize new chemicals and strengthen academia-industry relationships. This interdisciplinary project will strengthen the PI's deep commitment to mentoring students and post-doctoral scholars, and provide a unique training environment for plant biology, genetics, and chemistry.The researcher has made key contributions to understanding the function of the ABA receptors and in developing synthetic ABA-mimicking compounds. In spite of the tremendous progress made, our current understanding of ABA receptor function has been hampered by genetic redundancy. This proposal asks a simple question: why do plants need so many ABA receptors? In this proposal, the PI will define which receptors play a predominant role in modulating water relations and systematically dissect the roles of different receptors in mediating ABA's concentration-dependent effects. To do this the PI will employ a series of complementary chemical, genetic, and synthetic biological approaches. In one experimental approach, synthetic small molecules that activate either the high- or low-affinity receptors will be used to interrogate the roles of different receptors in distinct ABA responses. Small molecules are powerful probes of biological pathways but can be limited by "off-target" effects that can complicate interpretation of data. To address this limitation, the PI will also use synthetic biological strategies and engineer receptors that can be selectively controlled by a non-natural chemical. The likelihood of structurally unrelated molecules having identical off-target effects is low, therefore this strategy complements the first strategy. Lastly, genome editing will be coupled with classical genetic approaches to generate sets of plants that lack the different receptor subtypes. These materials will be characterized along with the other materials to build an integrated and systematic understanding of the functions of the ABA receptor family.