By Ikon Kim
June 7, 2026 · 3 min readResearchers in China uncovered the peptide signals that let pollen survive cold, recovering 18.3% of lost grain yield in rice even as climate change makes the sudden cold snaps that wreck harvests more frequent.
The discovery hands plant breeders a molecular lever against an overlooked side of climate change, the abrupt cold spells that sterilize flowers and gut harvests across major growing regions.
A team led by Cao Xu at the Chinese Academy of Sciences traced the rescue to two small signaling molecules, SlRGF9 and SlRGF10, that tomato flowers switch on only when the temperature drops, the group reported in Nature.
Until now, scientists knew that cold wrecked pollen but could not name the molecular switch behind the failure, leaving breeders without a clear target.
The molecules stay silent in warm weather, so plants carrying extra copies grow normally and pay no yield penalty until the cold actually arrives.
These peptides latch onto a surface receptor called SlRGFR6 and unleash a rush of calcium into the anther, the flower structure that feeds developing pollen.
Cold normally stalls the orderly death of those nurse cells, starving the pollen before it matures, but the calcium signal keeps that cleanup on schedule, and the grains survive.
Switching those peptides on lets rice plants claw back 18.3% of the grain they would otherwise surrender to cold, while modified tomato plants dodged up to 52% of their cold-driven losses.
In winter greenhouse trials, the engineered tomatoes held onto fruit that unprotected plants dropped, turning a barren cold spell into a near-normal harvest.
To prove the fix outdoors, the group grew altered rice through cold snaps in paddies across northern and southern China, where the plants set far more filled grains than their unchanged neighbors.
Pollen ranks among the most delicate tissues a plant builds, and a 2021 study found that cold during flowering jams another opening and leaves rice florets sterile.
The danger already cuts deep, since an EGU analysis found that extreme cold struck 27% of China's rice seasons in recent decades, shaving average yields by about 12% and biting hardest during the flowering window.
A bad cold year can punish growers far more than the averages suggest, slashing yield in some rice varieties by more than a third and leaving others nearly barren.
Climate change rarely means steady warmth, and farmers increasingly face violent swings that can drop a killing frost onto fields in the middle of a warm stretch.
Farmers long lifted output by plowing more land and pouring on fertilizer, but that playbook strains against shrinking acreage and a hotter, more erratic climate.
The new work points the other way, toward shielding the harvest already in the ground, a strategy that gains urgency as a 2025 analysis projects global food demand rising at least 50% by 2050 while every extra degree of warming carves into rice and wheat yields.
Because the same peptide circuit threads through both tomato and rice, two distantly related crops, the authors report it likely runs through other staples and could speed the breeding of cold-tough wheat and maize.
Wheat and maize feed much of the planet, so even a modest cold-resilience boost in those grains could ripple out to billions of meals.
The rescue so far rests on greenhouse and field trials rather than crops in farmers' rows, and the team has filed patents on the peptides while it works to breed the trait into varieties growers can plant.
