The Role Of Brassinosteroid Inactivation In Plant Development

维生素C是植物生长所需的生长促进激素。大多数研究都集中在油菜素类固醇的生物合成或其响应途径。相反，Neff小组研究了油菜素类固醇的失活，并证明了这一过程对植物发育的重要性。为了获得更全面的了解，Neff小组扩大了他们的研究范围，包括所有五种潜在的油菜素类固醇失活酶。本研究将验证以下假设：1）五种不同的油菜素类固醇失活途径在发育中具有冗余和不同的作用。Neff实验室将使用分子，遗传和生化分析来检查这些油菜素类固醇失活途径中的每一个之间的潜在重叠。2)五种不同的油菜素类固醇失活途径具有重叠和不同的调节机制。Neff小组已经鉴定了一种转录因子，它调节CYP 734 A1的表达和植物对最活跃的油菜素类固醇，油菜素内酯的反应。他们将扩大这些分子/遗传学研究，包括拟南芥中的所有五个油菜素类固醇失活基因。3)CYP 72 C1使用无活性的油菜素前体作为调节激素水平的底物。通过在植物中或异源表达系统中过表达来鉴定CYP 72 C1产物的早期尝试涉及用芸苔素进行的饲养研究。然而，Neff小组最近发现CYP 72 C1不使用油菜素作为底物，而是优先结合生化前体。他们已经与激素生物化学家建立了国际合作，并将使用多种表达系统与生化分析相结合来鉴定CYP 72 C1活性的产物。拟议活动的更广泛影响：这项工作可能会影响植物研究的多个领域，包括植物激素，基因调控和发育过程中的遗传相互作用。这些研究将直接有助于两个博士的教育。学生以及本科生在内夫组。与过去一样，这些研究的结果将在同行审查的出版物、国家和国际会议以及当地公立学校中介绍。

Brassinosteroids are growth-promoting hormones that are required for plant development. Most investigations have concentrated on either brassinosteroid biosynthesis or on their response pathways. In contrast, the Neff group studies brassinosteroid inactivation and has demonstrated the importance of this process with regard to plant development. To gain a more comprehensive understanding, the Neff group has expanded their studies to include all five potential brassinosteroid inactivating enzymes. The following hypotheses will be tested in this study: 1) The five different brassinosteroid-inactivating pathways have redundant as well as distinct roles in development. The Neff lab will use molecular, genetic and biochemical analysis to examine the potential overlap between each of these brassinosteroid-inactivating pathways. 2) The five different brassinosteroid-inactivating pathways have overlapping and distinct regulation mechanisms. The Neff group has identified a transcription factor that modulates both CYP734A1 expression and plant responses to the most-active brassinosteroid, brassinolide. They will expand these molecular/genetic studies to include all five brassinosteroid-inactivating genes in Arabidopsis. 3) CYP72C1 uses inactive brassinolide precursors as a substrate for regulating hormone levels. Early attempts at identifying CYP72C1 products via over-expression in plants or in heterologous expression systems involved feeding studies with brassinolide. However, the Neff group has recently discovered that CYP72C1 does not use brassinolide as a substrate, instead preferentially binding biochemical precursors. They have established international collaborations with hormone biochemists and will use multiple expression systems coupled with biochemical analysis to identify the product of CYP72C1 activity. Broader impact of the proposed activity: This work will likely impact multiple areas of plant research including studies of: plant hormones, gene regulation, and genetic interactions during development. These studies will contribute directly to the education of two Ph.D. students as well as undergraduate students in the Neff group. As in the past, results from these studies will be presented in peer-reviewed publications, in national and international meetings as well as in local public schools.