CAREER: Karrikin and strigolactone signaling mechanisms in Arabidopsis

David C NELSONPROPOSAL IOS-1350561CAREER：拟南芥中的Karrikin和Strigolacone信号机制Karrikins是最近发现的一类化合物，在烟雾中发现，它能激活许多植物物种在火灾后的萌发。Strigolactone是一类调节枝条、根构型和形成层生长的植物激素家族。Strigolactone还能激发高度破坏性的寄生杂草、高粱和独脚金的萌发，并促进与丛枝菌根真菌的共生。了解卡瑞金和斯特里内酮控制植物生长的分子机制可能会在作物发展和杂草控制方面带来新一轮的创新。植物通过一条需要F-box蛋白Max2的遗传途径识别卡里金和斯特里内酮。F-box蛋白在几种植物激素信号系统中发挥核心作用，并通过靶向特定的蛋白质底物进行降解。Max2的靶点长期以来一直难以捉摸，因此是理解karrikin和strigolacone信号转导机制的关键障碍。基因筛选现在已经导致了一个候选靶点的确定，即Max2 1抑制因子(SMAX1)，它调节种子萌发和幼苗生长。SMAX1是模式植物拟南芥中一个由八个基因组成的未知家族的成员。在这个项目中，将使用遗传和生化方法来确定1)SMAX1家族中的其他基因如何对植物发育做出贡献；2)SMAX1蛋白的分子功能和调控；以及3)SMAX1和Max2的蛋白相互作用伙伴。这些实验将揭示SMAX1家族如何在karrikin和strigolacone信号转导中发挥作用，以及SMAX1是否是Max2的靶标。一名博士后研究员、研究生和几名本科生将接受科学相关领域的职业培训。将启动两个项目，以提高本科生在与科学相关的职业中的留存率，并加强K-12 STEM教育。该项目的发现将通过同行评议期刊上的出版物和在科学会议上的陈述来传播。

DAVID C NELSONPROPOSAL IOS-1350561CAREER: Karrikin and strigolactone signaling mechanisms in ArabidopsisKarrikins are a recently discovered class of compounds found in smoke that activate germination of many plant species after fire. Strigolactones comprise a family of plant hormones that regulate shoot branching, root architecture, and cambial growth. Strigolactones also trigger germination of the highly destructive parasitic weeds, broomrape and witchweed, and promote symbiotic associations with arbuscular mycorrhizal fungi. Understanding the molecular mechanisms by which karrikins and strigolactones control plant growth may enable a new wave of innovation in crop development and weed control.Plants recognize both karrikins and strigolactones through a genetic pathway that requires the F-box protein MAX2. F-box proteins have central roles in several plant hormone signaling systems, and act by targeting specific protein substrates for degradation. The targets of MAX2 have long remained elusive and as such represent a critical roadblock to understanding the mechanism of karrikin and strigolactone signaling. A genetic screen has now led to the identification of a candidate target, SUPPRESSOR OF MAX2 1 (SMAX1), which regulates seed germination and seedling growth. SMAX1 is a member of an uncharacterized family of eight genes in the model plant Arabidopsis thaliana. In this project genetic and biochemical approaches will be used to determine 1) how other genes in the SMAX1 family contribute to plant development; 2) the molecular function and regulation of SMAX1 protein; and 3) the protein interacting partners of SMAX1 and MAX2. These experiments will reveal how the SMAX1 family acts in karrikin and strigolactone signaling and whether SMAX1 is a target of MAX2. A postdoctoral researcher,graduate student, and several undergraduates will be trained for careers in science-related fields. Two projects will be initiated to improve undergraduate retention in science-related careers and enhance K-12 STEM education. The discoveries from this project will be disseminated through publications in peer-reviewed journals and presentations at scientific conferences.