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.

Agency
National Science Foundation (NSF)
Institute
Division of Integrative Organismal Systems (IOS)
Application #
1556171
Program Officer
Anne W. Sylvester
Project Start
Project End
Budget Start
2016-06-15
Budget End
2019-11-30
Support Year
Fiscal Year
2015
Total Cost
$630,660
Indirect Cost
Name
Cold Spring Harbor Laboratory
Department
Type
DUNS #
City
Cold Spring Harbor
State
NY
Country
United States
Zip Code
11724