A Novel Mechanism Regulating Inflorescence Development in Tomato

在自然界和农业中，植物的生产力都依赖于花朵，花朵是果实和种子的基础。根据植物的不同，在生殖枝上形成的花的数量，即所谓的花序，可能会有很大的差异。发现导致这种物种特异性多样性的基因，并了解这些基因如何共同作用来控制花的生产，是植物生物学中的一个主要焦点，与作物改良直接相关。在茄科茄科番茄及其近亲，如茄子、辣椒和土豆中，每个花序上的花产量差异很大，从单一枝条上的单花，如辣椒，到许多枝条上的数十朵花，如几个野生西红柿。这个项目将利用在番茄中发现的花生产的变异来研究一组基因，这些基因是产生多花花序所必需的，从而研究所有番茄品种所熟悉的“藤上番茄”的结构特征。通过使用新的基因编辑技术突变这些基因，将有可能剖析这些基因编码的蛋白质如何精确地控制每株番茄植株何时、何地以及产生多少花和果实。该项目的结果将揭示新的花卉生产基因及其作用模式，然后可以利用经典和现代遗传工具对其进行针对性的修改，以提高番茄和许多相关作物的产量。此外，市中心一所中学的外展项目将对年轻学生进行基因工程过程的教育，以帮助摆脱对转基因食品的普遍误解。所有地上植物的生长都源于茎分生组织，这是一种干细胞的小群体，可以产生巨大的建筑多样性，特别是在花序中。这种多样性的核心是一个关键的、但鲜为人知的分生组织成熟过程。植物发育中的一个主要问题是如何在不同的植物中控制分生组织成熟的时间，从而控制花序和花的产生。与其他模式植物中关于分生组织成熟的知识相比，在番茄和相关茄科中所知的要少得多，尽管它代表了广泛的合生生长习性。最近对番茄的研究揭示了一个新的成熟程序，它由TMF基因编码的一个新的转录调节因子定义。该项目结合遗传学、基因组学和生物化学来研究TMF及其相互作用的蛋白质伙伴调控分生组织成熟的机制。在目标1中，将从遗传、分子和发育角度研究TMF转录辅助因子。在目标2中，将通过整合RNA-SEQ和CHIP-SEQ来探索TMF及其表达网络的转录靶点。在目标3中，将使用CRISPR/CAS9来描述TMF家族成员的特征。该项目包括第一个分子机制研究，以了解如何微调分生组织成熟，以定量控制合生植物的花生产。这些发现将揭示分生组织成熟的新原理，使花序结构和花卉生产的调节有利于农业。

In both nature and agriculture plant productivity depends on flowers, which are the foundation for fruits and seeds. Depending on the plant, the number of flowers that form on reproductive branches, known as inflorescences, can vary substantially. Discovering the genes responsible for this species-specific diversity, and understanding how these genes work together to control flower production, is a major focus in plant biology with direct relevance for crop improvement. In tomato and its close relatives in the nightshade (Solanaceae) family, such as eggplant, pepper, and potato, flower production on each inflorescence varies dramatically, from a solitary flower on a single branch, as in pepper, to dozens of flowers on many branches, as in several wild tomatoes. This project will take advantage of variation in flower production found in tomato to study a group of genes that are required for generating multi-flowered inflorescences, and thus the familiar "tomatoes-on-the-vine" architecture characteristic of all tomato varieties. By mutating these genes using new gene-editing technology, it will be possible to dissect how the proteins encoded by these genes control precisely when, where, and how many flowers and fruits are produced on each tomato plant. Results from this project should reveal new flower-production genes and their modes of action, which can then be targeted for modification using both classical and modern genetic tools to improve yields in tomato and many related crops. Additionally, an outreach program at an inner-city middle school will educate young students on the process of genetic engineering to help shed popular misconceptions about genetically modified food.All above ground plant growth originates from shoot meristems, small populations of stem cells that give rise to vast architectural diversity, particularly in inflorescences. At the heart of this diversity lies a critical, yet poorly understood, process of meristem maturation. A major question in plant development is how timing of meristem maturation, and thus inflorescence and flower production, is controlled in different plants. Compared to knowledge on meristem maturation in other model plants, much less is known in tomato and related Solanaceae, despite representing the widespread sympodial growth habit. Recent work in tomato has exposed a new maturation program, defined by a novel transcriptional regulator encoded by the TMF gene. This project integrates genetics, genomics and biochemistry to study the mechanisms by which TMF and its interacting protein partners regulate meristem maturation. In Aim 1, TMF transcriptional co-factors will be studied genetically, molecularly, and developmentally. In Aim 2, transcriptional targets of TMF and its expression network will be explored by integrating RNA-seq and ChIP-seq. In Aim 3, TMF family members will be characterized using CRISPR/Cas9. This project comprises a first molecular mechanistic study to understand how meristem maturation is fine-tuned to quantitatively control flower production in sympodial plants. The findings should reveal new principles of meristem maturation that can enable modulation of inflorescence architecture and flower production to benefit agriculture.