CAREER: Defining Spatiotemporal Regulation and Integration of phytochrome B Signaling Complexes

Light, temperature, and nutrient availability are fundamental signals that dictate how plants adapt their growth and development to survive in changing surroundings. Because plants are stationary, they must constantly monitor their soil and atmospheric conditions optimize their growth and photosynthesize. At the cellular level, these cues are sensed and integrated by specialized signaling complexes that operate across different parts of the cell. In the nucleus, these complexes assemble into structures called photobodies to process light and temperature. In the rest of the cell, other complexes coordinate vital cellular responses. This CAREER project aims to identify the specific molecular components that make up these cellular complexes under differing conditions of light, temperature, and nutritious amino acid levels to determine how the plant regulates growth and development. By using innovative microscopy and gene-editing tools to discover these components, this research will provide foundational advances in plant biotechnology. Uncovering these core cellular mechanisms provides essential knowledge to improve crop resilience, increase agricultural yields, and support long-term food security. The project also supports science education by engaging elementary school children via microscopy-based public outreach, and training high school, undergraduate, and graduate students through interdisciplinary research experiences designed to nurture the next generation of scientists. To adapt to dynamic environments, plants rely on the precise spatial organization and molecular rewiring of cellular signaling networks. While biomolecular condensates in the nucleus, specifically phytochrome B photobodies, act as central hubs for integrating light and temperature signals, these microdomains are compositionally heterogeneous, continuously remodeling their molecular makeup to multiplex and process distinct environmental stimuli. However, the precise in vivo molecular architecture of these heterogeneous complexes, their dynamic composition under shifting conditions, and their functional interfaces with distinct cytoplasmic phytochrome B complexes remain poorly understood. This CAREER project investigates the dynamic molecular composition, subcellular trafficking, and downstream signaling mechanisms of nuclear photobodies and cytoplasmic phytochrome B-interacting complexes under fluctuating light, temperature, and amino acid-deficient conditions. This project employs an interdisciplinary approach combining confocal imaging, broadly applicable live cell proximity-labeling platforms, quantitative proteomics, and advanced genome editing. The research will systematically map the spatiotemporal interactomes of these signaling complexes to identify novel interacting components and track their conditional relocation between cellular compartments. Genetic and biochemical analyses will determine how specific environmental perturbations alter the molecular composition and function of nuclear photobodies and cytoplasmic phytochrome B complexes, and how these molecular adjustments regulate downstream transcriptional networks controlling growth and development. By elucidating these interconnected signaling nodes, this project will reveal fundamental biochemical and biophysical principles governing signal integration in multicellular organisms. In addition, the project will generate high value genomic, proteomic, and transgenic resources to drive advancements in modern plant biotechnology for the broader scientific community. 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.