ORANGE: a tale of two pigments and two organelles.
Liu J, Lu S
Crispr
When a tomato on your vine shifts from green to deep orange as it ripens, a single protein is choreographing that entire transformation — and researchers have now pinpointed the one-letter DNA change that turns that color dial all the way up, opening a path to nutrient-denser crops bred through precision editing rather than transgenic methods.
Plants have a remarkable multitasking protein that works in two places at once inside the cell — one copy boosts the production of orange and yellow health-promoting pigments, while another copy in the cell's command center controls how the plant builds its light-harvesting machinery. Scientists found that a single tiny change in the instructions for making this protein floods the plant with pigment, turning cauliflower orange and potentially doing the same for tomatoes, potatoes, and rice. That same protein also helps plants cope with heat and drought, making it a promising target for building more nutritious, climate-resilient crops.
Key Findings
The OR protein operates simultaneously in two organelles — in plastids it stabilizes the enzyme that kickstarts carotenoid pigment production, and in the nucleus it interacts with TCP transcription factors to regulate chloroplast development during light-triggered growth
A single point mutation called the 'golden SNP' is sufficient to dramatically boost carotenoid accumulation and trigger chromoplast formation, and CRISPR tools can now introduce this change in tomato, potato, rice, and sorghum without transgene insertion
OR protein evolved through gene duplications in early land plants such as mosses, diversifying into OR and OR-Like subfamilies — the chromoplast-specializing functions appear to be an innovation of vascular plants and are absent in algae
chevron_right Technical Summary
The ORANGE (OR) protein acts as a dual-purpose switch in plants, simultaneously ramping up orange and yellow pigment production in one part of the cell while regulating how chloroplasts develop in another. A single naturally occurring mutation called the 'golden SNP' dramatically cranks up this pigment dial, and scientists are now using CRISPR to introduce that same tweak into food crops without traditional GMO regulatory hurdles.
Abstract Preview
The ORANGE (OR) protein family exemplifies evolutionary innovation in plants, acting as dual-localized regulators coordinating nuclear transcription and plastidial metabolism. Discovered in the cau...
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