Single Gene Rewrite: How a Purple Fruit Rewrote the Rules of Citrus Flavor and Color

For the first time, researchers have discovered a single gene that simultaneously controls both the sourness and the colour of citrus fruit. The study identifies a transcription factor called PH4‑Like in the purple wampee, a rare citrus relative, that independently regulates the accumulation of citric acid--which gives fruit its tangy flavour--and anthocyanins, the pigments responsible for red, purple and blue hues.