Presentation description

Global climate change has led to a steady rise in temperature since pre-industrial times, making plant thermotolerance a necessity for survival. Heat stress negatively impacts plant growth and resilience by interfering with physiological processes. To mitigate these effects, plants have evolved protective mechanisms that preserves cellular function and important structures including organelles like chloroplasts. As the site of photosynthesis and a key driver of plant growth and development, the chloroplast plays a central role in sensing environmental stress and initiating adaptive responses. NUCLEAR CONTROL OF PEP ACTIVITY (NCP) is a chloroplast- and nucleus-localized protein that plays roles in two major photomorphogenic developmental processes: hypocotyl growth inhibition and chloroplast biogenesis in Arabidopsis thaliana (Arabidopsis). Sequence analysis revealed that NCP contains a predicted intrinsically disordered region (IDR), but its function remains unknown. Given that IDRs often drive liquid-liquid phase separation (LLPS), I hypothesized that the IDR of NCP enables LLPS and contributes to heat stress adaptation. To test this, I performed molecular cloning and protein purification to express and isolate recombinant GFP-tagged NCP protein. In vitro assays revealed that GFP-NCP undergoes LLPS and forms liquid-like droplets in the presence of PEG as a molecular crowding agent. Notably, heat stress significantly enhanced droplet formation. I propose that heat-induced condensation of NCP promotes chloroplast-mediated protective responses and enhances plant survival under heat stress conditions.