Yoo et al., 2019 Nature Communications 10:2629

Understand functions of photobodies in chloroplast biogenesis

Eukaryotic cell contains various biomolecular condensates consisting of protein/RNA/chromatin complexes, which are generally formed through liquid-liquid phase separation. The misregulation of phase transition is associated with various human diseases such as neurodegenerative diseases and cancer. In plants, photobodies are photoreceptor-containing biomolecular condensates that sense light and control almost every aspects of growth and development including chloroplast biogenesis. The misregulation of photobodies is associated with defects of chloroplast biogenesis, leading to albino phenotype (absence of functional chloroplast). We aim to identify the molecular and cellular mechanisms by which photobodies control biogenesis of chloroplasts (green plastids), with a particular focus on nucleus-to-plastid signaling pathways, using molecular biology, cell biology, and genetic approaches.

Willage et al., 2021 Nature Genetics 53:955-961

Investigate functions of photobodies as environmental sensors

The formation of photobodies is considered to be driven by a biophysical process called liquid-liquid phase separation (LLPS). Accumulating evidences suggest that environmental stresses may drive phase separation of photobodies to control functional properties of photobodies and quickly adapt to environmental changes. For example, plants grown under white light (sun light) are short as PHYB photoreceptor and PIF7 (a member of Phytochrome-Interacting transcription Factors) colocalize in discrete photobodies. Shade light (low red:far-red ratio) abolish photobody localization, making plants grow taller to look for sun light and improve photosynthesis in chloroplasts. Our lab is interested in molecular and cellular mechanisms by which environmental changes modulate phase separation of photobodies and photobody-controlled chloroplast biogenesis.

Identify novel regulators of the nucleus-to-plastid signaling pathway

The photobody-controlled nucleus-to-plastid signaling pathway provides a new framework that can be expanded to uncover molecular genetic networks of nucleus-chloroplast communication. We aim to identify novel regulators of the nucleus-to-plastid signaling pathway, which will ultimately lead to discover the nucleus-to-organelle signaling molecule. The long-term goal is to understand regulatory mechanisms of nucleus-chloroplast communication to improve photosynthesis and yield stability in response to environmental stresses.