bioRxiv · 2026-05-23
Scientists discovered a single gene in rice that controls the size and number of bundle sheath cells — the specialized cells that give C4 plants like corn their superior efficiency. Knocking out this gene nudges rice one step closer to the high-yielding C4 photosynthesis system, potentially pointing toward rice varieties that produce 50% more grain with less water and fertilizer.
Knocking out the OSA3 gene in rice reduced bundle sheath cell length by decreasing acid secretion into the cell wall space, confirming that 'acid growth' controls cell elongation in these key leaf cells.
Edited rice plants showed increased bundle sheath cell number and greater chloroplast occupancy — two hallmarks of the high-efficiency C4 photosynthetic system found in crops like corn.
C4 photosynthesis can raise crop yield by up to 50% compared with the C3 pathway used by rice, and OSA3 represents a single-gene entry point toward engineering that transition.
