Chinese scientists have discovered through a decade-long study that rice can pass cold resistance to future generations through epigenetic mechanisms without changing the genome. The study, published in the journal Cell, provides important evidence that environmental stress directly induces heritable adaptation.
Researchers from the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences selected Oryza sativa L, a low-temperature-sensitive Asian rice variety, and subjected it to a low temperature of minus 15°C during its reproductive growth period, and screened cold-tolerant offspring. After three generations, some plants can still maintain high yields under low temperature stress. Genome sequencing ruled out the influence of DNA mutations, indicating that cold tolerance is not driven by changes in genetic sequence. Further analysis found that chemical markers (such as methylation modifications) at the beginning of the ACT1 gene in cold-tolerant rice were significantly reduced. Experiments have confirmed that artificially reducing these marks can enhance the cold tolerance of plants, while restoring the marks makes this characteristic disappear, directly proving the key role of epigenetic modifications.
The research team also analyzed 131 rice varieties in China and found that varieties in cold northern regions generally have fewer chemical markers of the ACT1 gene, while varieties in warm southern regions are rich in this marker, indicating that this epigenetic feature may promote the adaptive spread of rice to high latitudes.
Experts commented that this research challenges the traditional evolutionary view that adaptability can only be gradually formed through natural selection of DNA mutations. Although epigenetic phenomena (such as environmental toxins affecting the health of offspring) have been found in animal studies, cases such as cold tolerance in rice that directly benefit environmental adaptation are still rare.