PubMed · 2026-06-12
Scientists used CRISPR gene editing in rice to trace how plants produce oxalate — the compound behind spinach's gritty texture and rhubarb's sourness — and found that the cell's sugar-burning process (glycolysis) is the primary driver, overturning the long-held assumption that photorespiration was mainly responsible.
CRISPR-knockout rice plants lacking nitrate or nitrite reductase showed significantly lower oxalate levels; restoring nitrate or nitrite (but not ammonium) rescued production, pinpointing exactly which step in nitrogen processing controls oxalate.
Glycolytic intermediates (phosphoenolpyruvate and 3-phosphoglycerate) boosted oxalate content, while two glycolysis inhibitors suppressed it — directly confirming that sugar metabolism, not photosynthesis-linked respiration, drives oxalate synthesis.
Photorespiration does not directly produce oxalate; it acts only indirectly through glycerate, which feeds back into glycolysis — overturning a long-standing assumption about the primary biosynthetic route.
