Control of Shoot apex indeterminacy by TERMINAL FLOWER1

枝条结构-枝条的分枝模式以及它何时/在哪里开花-对于自然环境中的植物在生长季节产生足够的后代和作物的产量(生物量或果实/种子)非常重要。瓦格纳实验室正在研究一种蛋白质，这种蛋白质可以调节所有开花植物的枝条结构。该项目的长期目标是针对不同的环境条件和不同的植物用途，一方面是叶类蔬菜和生物燃料，另一方面是水果和谷物，精确地调整苗木结构。为了实现这一目标，实验室正在将可诱导的遗传操作与高分辨率的空间和时间测量相结合，这将有助于微调这一过程。除了找到增强粮食安全的可持续解决方案外，社会福利还包括在为期两个学期的本科研究经验(CURE)实验室课程中，培训20名本科生从事对这一提议至关重要的研究。根据活体数据和模型，决定枝条构型的一个关键因素是主枝和侧枝原基采用花的命运的时间。许多实验室的研究表明，末端FLOWER1基因及其同源基因在阻止顶端的确定性(花的命运)方面起着关键作用。在tfl1突变体中，新梢成为顶花，导致地上干细胞库的分化。在这项建议中，我们解决了基本的发育生物学问题，即TFl1如何控制茎尖端干细胞的维持(不确定性)或分化(确定性)。此外，减少的TFL1积累或活性使包括番茄、大豆和棉花在内的几种作物发生了革命性的变化，因为地上部的决定性使得可以通过密集种植来实现可持续的增产。然而，人们对TFl1的积累是如何控制的知之甚少。我们将确定促进TFL1在茎尖上调的增强子和转录因子。TFL1如何阻止确定性也是未知的。我们将确定在芽中直接抑制TFL1的关键基因和途径，以促进含有茎尖的干细胞库的分化。所获得的洞察力将促进对从干细胞维持到芽顶端分化的转换、芽结构是如何控制的，并有助于实现未来对农学重要试验的量身定制工程的理解。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Shoot architecture – the branching pattern of a shoot and when/where it forms flowers - is important for plants in natural environments to make sufficient offspring in the growing season and for yield (biomass or fruits/seeds) in crops. The Wagner lab is investigating a protein that regulates shoot architecture in all flowering plants. The long-term goal of this project is to precisely modulate shoot architecture for different environmental conditions and for different plant uses, leafy vegetables and biofuels on one hand or fruits and grains on the other. To achieve this goal, the lab is coupling inducible genetic manipulations with high resolution spatial and temporal measurements changes in the accumulation of unknown regulators of shoot architecture that will help fine-tune this process. Besides finding sustainable solutions for enhancing food security, societal benefits include training 20 undergraduate students in research important for this proposal in two semester-long Course-based Undergraduate Research Experiences (CURE) laboratory courses. Based on in vivo data and modeling, a key determinant of shoot architecture is the time at which the main shoot and the lateral primordia adopt floral fate. Work by many laboratories points to a pivotal role of the TERMINAL FLOWER1 gene and its orthologs in preventing determinacy (flower fate) of the shoot apex. In tfl1 mutants, the shoot becomes a terminal flower leading to differentiation of the above ground stem cell pool. In this proposal we address the fundamental developmental biology question how maintenance (indeterminacy) or differentiation (determinacy) of the stem cells in the shoot apex are controlled by TFL1. Moreover, reduced TFL1 accumulation or activity revolutionized several crops including tomato, soybean, and cotton because shoot determinacy enables sustainable yield increases by allowing dense planting. Yet how TFL1 accumulation is controlled is poorly understood. We will identify enhancers and transcription factors that promote TFL1 upregulation in the shoot apex. It is also not known how TFL1 blocks determinacy. We will define key direct TFL1- repressed genes and pathways in the shoot that promote differentiation of the stem cell pool containing shoot apex. Insight gained will advance understanding of the switch from stem cell maintenance to differentiation at the shoot apex, how shoot architecture is controlled, and help enable future tailored engineering of agronomically important traits.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.