In what’s been heralded as a research breakthrough, scientists have discovered a gene variant that makes rice more resilient, enabling plants to produce almost 80% more grain under heat-stressed conditions, compared to more heat-sensitive counterparts.
The discovery could be transformative for Asian rice farms, where most rice is grown and where farmers already battle with the effects of excess heat on crops. For years in fact, farmers and scientists have puzzled over why rice grown in high temperatures often develops a chalky texture, and crumbles easily into fragments of low quality grain. These quality issues are also linked to lower rice yields overall.
This challenge kicked off a huge research mission that began back in 2012, when the group of Chinese researchers on the new Cell paper went in search of rice genes that may be associated with heat resilience. Choosing several hundred rice strains, they grew these in multiple locations across China that experience differing temperatures—including continuously high temperatures and heat waves.
From each of these plants, the researchers took rice grains, dried them out, and then visually assessed the grains for their translucency or opacity. Opaque grains indicated that they were chalky and had been damaged by the heat, whereas clearer grains were less chalky and therefore an indicator that those plants may be more resilient to high temperatures.
From this, the team selected some strains that produced a higher percentage of translucent grains. And when they dug into the genomes of those promising varieties, they pinpointed a candidate gene that seemed to be implicated in rice plants’ heat-response. They labelled this gene ‘QT12’.
They found that high temperatures can cause elevated expression of QT12, and that this in turn seems to affect the protein-starch ratio that the rice packs into its grains—increasing the amount of starch and reducing the protein, which results in chalkier seeds. But there was also more to QT12, as it turned out: the gene comes with an ‘on-off’ switch, the researchers found—meaning that in some cases, rice plants contain variants of this gene that don’t express when exposed to higher temperatures.
In a new set of experiments, the research team bred these newly-discovered QT12 variants into a normally heat-sensitive rice variety called Huazhan. Then they planted plots of this experimental rice again at different locations in China where soaring temperatures are a regular occurrence.
They found that even under high temperatures, not only did the bred rice produce better-quality, significantly less chalky grain, but its yield was also strikingly larger: in fact grain yield per plot was between 31.2% and 77.9% higher than the regular temperature-sensitive Huazhan across the different sites.
It seems that the discovered QT12 variants have a protective quality on the developing seeds, shielding them from heat. What’s striking, say the researchers in their paper, is that they’ve found a gene that seems to hit two birds with one stone—one that “synergistically maintains grain quality and yields under natural high temperatures”.
Rice is a staple for over half of the world, and as that world grows warmer, the vulnerability of this crucial foodstuff is a rising worry. It’s also a concern for the thousands of smallholder farmers in Asia whose economic fates are intertwined with rice quality and yields.
Heat-resistant rice could be revelatory for human nourishment and livelihoods. Meanwhile, not only is QT12 highly-conserved across thousands of rice variants, but also thousands of other plant species including grain crops, vegetables, and fruits, the researchers report in their work. They’re therefore confident that their discovery “could also be employed for breeding other thermotolerant crops for a warmer future.”
Li et. al. “A natural gene on-off system confers field thermotolerance for grain quality and yield in rice.” Cell. 2025.
Photo by Danang DKW
