In a recent study conducted by specialists from the Institute of Genetics and Developmental Biology at the Chinese Academy of Sciences, arguments regarding the adaptation of rice to cold during its expansion northward were discovered. The research results were published in the scientific journal Cell. DOI: 10.1016/j.cell.2025.04.036
Under the guidance of Professor Cao Xiaofen, a team of scientists presented evidence that DNA methylation is a form of epigenetic modification or gene expression regulation that plays a key role in the transgenerational transmission of acquired cold resistance ability in rice, confirming Lamarckian ideas.
Researchers traced the evolutionary trajectory of rice spreading northward into colder regions within this study.
Using an innovative multi-generational screening system targeting key developmental stages of cold-sensitive rice, they conducted targeted work over three generations to identify and breed rice plants better suited to cold conditions.
This approach allowed the creation of stable rice lines with improved cold tolerance traits dominant in inheritance models. It was shown that this resilience is maintained for at least five generations, even after the stress is removed.
Multi-level analysis revealed hypomethylation in the promoter of ACT1 (arabinogalactan-coding gene) as a significant epigenetic alteration.
Scientists applied a DNA methylation editing system to precisely modify the methylation of the ACT1 arabinogalactan gene promoter. This led to targeted regulation of cold tolerance, confirming that promoter hypomethylation induced by cold results in ACT1 activation, validating the role of epigenetic changes.
Further, researchers studied the molecular basis of this epigenetic regulation, identifying the underlying mechanism. They showed that cold stress reduces the expression of the methyltransferase MET1b, disrupting the preservation of methylation in the ACT1 promoter, leading to the formation of hypomethylated epiallele.
Additional studies showed that the variability region of the ACT1 promoter methylation contains a binding site for the transcription activator Dof1, whose sensitivity depends on the DNA methylation status. Inactivating Dof1 significantly reduces cold tolerance at the growth stage, establishing the cold stress regulation chain → MET1b regulation decrease → ACT1 promoter demethylation → enhanced Dof1 binding → ACT1 activation → increased cold tolerance.
Natural variation studies showed that despite the highly conserved coding sequences of ACT1, the DNA methylation status demonstrated polymorphism closely linked to cold tolerance.
Among 131 local rice varieties from three main regions of cultivation in China, over 88% of varieties from southern and central regions had hypermethylated ACT1, while varieties from the cold northeastern region significantly differed with hypomethylated ACT1.
This methylation gradient "high in the south, low in the north" indicates that ACT1 epigenetic changes were a central selection target during rice domestication and geographic distribution.
By analyzing the role of cold-induced epigenetic changes in rice adaptation, this study not only elucidates the molecular mechanism of rapid adaptation to the environment but also provides compelling support for alternative inheritance theories long overlooked in mainstream evolutionary biology.
Reviewers welcomed the work, noting: "This is crucial for understanding adaptive processes and indicates mechanisms that do not fit the traditional Darwinian paradigm."
In addition to theoretical conclusions, this study also offers practical recommendations for improving agricultural crops. Scientists propose a new breeding strategy - "stress diagnostics → epigenetic variant identification → precise editing" - to develop stress-resistant agricultural crops. This approach represents a promising path to address agricultural challenges posed by climate change.
