Figure: Salk Institute

Grafting is an agricultural practice that dates back nearly 3,000 years when people from ancient China to Greece realized that joining a cut branch from one plant to the stalk of another could improve crop quality. Recently, a study conducted by researchers from the Salk Institute and Cambridge University has shown that grafted plants share epigenetic traits. The team discovered that the two grafted plants keep their original genomes and do not share DNAs, but epigenetic information is being communicated within the plant.

The research team tracked the flow of epigenetic information by focusing on tiny molecules called small RNAs (sRNAs). The researchers designed a grafting experiment with three variations of Arabidopsis: two wild type varieties, while the third variety was a mutant bred to lack sRNAs of any kind. After each graft, the researchers observed that the plants were transmitting epialleles, the epigenetic equivalent of alleles.They also found that thousands of sites along the Arabidopsis genome were silenced by sRNAs.

The team agrees that the epigenetic effects of the mobile RNA are likely to be much greater with crop plants than in the model species used in their study. The two research groups are planning to explore these effects in tomatoes and other crops.

For more information, read the news release at Salk News.