Role of the Antiflorigen TFL1 in axillary meristem fate

植物与动物不同，当它们发现自己处于不适宜居住的环境中时，它们无法逃脱。取而代之的是，植物通过改变自己，改变它们的最终形态，或者通过推迟/加速其生命周期的各个阶段的过渡来应对。这些应对策略的关键是可以从植物的一个部位转移到另一个部位的小蛋白质，称为成花素和抗成花素。成花剂促进更快的发育和成花，而抗成花剂则相反。这两个监管机构相互对立，共同发挥着变阻器的作用。植物最终将遵循什么轨迹取决于成花素和抗成花素的相对丰度，这反过来又受温度、日照长度和其他线索的控制。成花素和抗花素的平衡如何改变植物的形态或其发育转变的速度？解决这个问题受到技术挑战的阻碍，成花素和反成花素可以调节其他关键调控因子的积累；但是，不要结合DNA来改变转录。主要研究人员已经克服了这些挑战，现在可以剖析植物中这些发育选择的决定是在哪里做出的，抗花剂实施的确切过程，以及它如何反对成花剂。从这些研究中获得的见解将具有广泛的普遍意义，因为这将促进对这些重要监管机构活动的了解，并对农业产生影响。不同作物中受成花素和抗成花素调控的性状包括：块茎形成、鳞茎形成、成芽和爆芽、种子休眠、依赖光周期的开花和花构型等关键农艺性状。本项目将利用最先进的遗传学、基因组、生化和细胞生物学方法，从机制上深入了解抗成花素(TFL1)调控的转录途径、其抑制活性以及与成花素(FT)的竞争作用部位。具体地说，成像和遗传学研究将探索FT是否像TFL1一样在腋生分生组织中积累并控制其命运。标准的和细胞类型特定的RNAseq结合网络分析将确定TFl1/Fd直接抑制的每条途径和关键成分。最后，双亲和纯化结合质谱学(在实验室课程中进行)将发现与TFL1复合体相互作用并塑造其活性的蛋白质。这些结合的活动将为植物形态和功能的关键调节者如何履行其职责这一问题提供新的机械洞察力。除了对本科生、研究生和博士后进行独立研究培训外，更广泛的影响还包括对女性科学家的指导，以及对40名本科生进行实验室课程研究的培训。在两门地道的研究性实验室课程中，学生将结合质谱学进行双亲和纯化，并对结果进行解读，并对他们的设计进行后续实验。最后，在宾夕法尼亚大学的暑期研究学院期间，将向高中生讲授这项提案中进行的研究。参与该项目的研究生将领导暑期研究学院的实验室部分、研讨会和训练营。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。

Plants - unlike animals- cannot escape when they find themselves in an inhospitable environment. Instead, plants cope by changing themselves, their final form or by delaying/accelerating the transition through phases in their lifecycle. Key to these coping strategies are small proteins that can move from one part of the plant to another, called florigen and antiflorigen. Florigen promotes more rapid development and flower formation, while antiflorigen has the opposite effect. The two regulators oppose each other and together act like a rheostat. What trajectory plants will eventually follow depends on the relative abundance of florigen to antiflorigen, which in turn is controlled by temperature, daylength and other cues. How does the balance of florigen and antiflorigen change plant form or the rate of its developmental transitions? Addressing this question has been hampered by technical challenges, florigen and antiflorigen can modulate accumulation of other key regulators; but, do not bind DNA to change transcription. The principal investigators have overcome these challenges and can now dissect where in the plant these developmental choice decisions are made, the precise processes put in place by antiflorigen and how it opposes florigen. Insights gained from these studies will be of broad general interest both by advancing understanding of the activity of these important regulators and by impacting agriculture. Traits modulated by florigen and antiflorigen in different crop species include such key agronomical traits such as tuberization, bulb formation, tree bud set and bud burst, seed dormancy, photoperiod-dependent flowering and flower architecture.This project will leverage state-of the-art genetic, genomic, biochemical and cell biological approaches to provide mechanistic insight into the transcriptional pathways regulated by antiflorigen (TFL1), its repressive activity and the site of competitive action with florigen (FT). Specifically, imaging and genetic studies will probe whether FT, like TFL1, accumulates in and controls fate of axillary meristems. Standard and cell type specific RNAseq combined with network analyses will identify the pathways and the key components in each directly repressed by TFL1/FD. Finally, dual affinity purification combined with mass spectrometry (conducted in laboratory course) will uncover proteins that interact with and shape activity of the TFL1 complex. The combined activities will provide novel mechanistic insight into the question how key regulators of plant form and function execute their roles. The broader impacts, besides training of undergraduate students, graduate students and postdocs in independent research, will include mentoring of female scientists and training of 40 undergraduate students in research in laboratory courses. Students in two authentic research lab courses will conduct dual affinity purification combined with mass spectrometry, interpret the results and conduct follow-up experiments of their design. Finally, a lecture on research conducted in this proposal will be given to high school students during a summer research academy at Penn. Graduate students involved in the project will lead summer research academy lab sections, workshops and boot camps.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.