PubMed · 2026-06-22
Plants use specialized proteins called phototropins to sense blue light and respond — bending toward windows, angling their leaves, opening pores, and repositioning chloroplasts. This review synthesizes 30 years of research on exactly how those proteins get switched on and off, revealing a precise molecular "phosphocode" that could be engineered to make crops and garden plants grow more efficiently.
Phototropins orchestrate at least 5 distinct light-driven responses — directional growth, chloroplast repositioning, stomatal opening, leaf positioning, and leaf flattening — all aimed at maximizing photosynthesis.
Specific patterns of chemical tags (phosphorylation) added to precise sites on phototropin proteins form a 'phosphocode' that determines which downstream response gets activated.
Protein phosphatases — enzymes that remove those chemical tags — play a newly recognized role in resetting and fine-tuning the phosphocode, suggesting the system is actively regulated in both directions.