In Arabidopsis, a cluster of genes produces small RNAs that may help silence genes in invading fungi and oomycetes.
Researchers found that producing small interfering RNAs is an ancient function of a conserved group of plant genes linked to pentatricopeptide repeat proteins. In Arabidopsis thaliana, the genes that supply these small RNAs are physically clustered on Chromosome 1.
The cluster has diversified through gene duplication, sequence changes and high-impact mutations, including changes that have turned some copies into pseudogenes. This process has produced a varied pool of small RNAs, which can silence target genes in invading fungal and oomycete pathogens. The pattern is consistent with these genes and pathogens influencing each other’s evolution over time.
How the genes diversify
The study identifies a conserved group, or clade, of pentatricopeptide repeat genes with an ancient role in producing secondary small interfering RNAs. These small RNAs contribute to plant immunity by silencing target genes in invading fungi and oomycetes.
In Arabidopsis thaliana, the genes that generate these small RNAs are physically clustered on Chromosome 1. The cluster has undergone gene duplication and extensive sequence diversification, including high-impact changes and pseudogenization, resulting in a diverse pool of small RNAs. The researchers classify these small-RNA-producing genes as a type of plant defense gene.
Evidence and caveats
The study combines analysis of gene conservation, chromosomal organization and sequence diversification with the known role of secondary small interfering RNAs in plant immunity. The reported evolutionary pattern is consistent with pathogen-driven diversification, but the abstract does not establish that explanation as direct proof of an arms race.
The abstract does not give sample sizes, identify particular fungal or oomycete species tested, or describe the details of functional experiments. It also does not report a disease-resistance improvement from engineering these genes, so the proposed engineering application remains a possibility for future work.
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Nature Communications · 2026 · DOI: 10.1038/s41467-026-77164-1
Authors: Feng Li, Yingnan Hou, AmirAli Toghani, Zhixue Wang, Bozeng Tang, Nicola Atkinson, Huijun Li, Qiao Yue, Yan Wang, Jianhua Ma, Jixian Zhai, Wenbo Ma
Institutions: Shanghai Jiao Tong University, Cornell University, Norwich Research Park, University of East Anglia, Southern University of Science and Technology, Scarborough Health Network, Sainsbury Laboratory, Department of Biological Sciences
