Researchers at the University of Sheffield have identified how plants maintain immune memory from past infections and how this memory can be reset, according to a study published in Nature Communications. Professor Jurriaan Ton and Dr. Adam Hannan Parker led the work.
Plants store immune memory by removing chemical tags attached to DNA that control gene expression without changing the genetic code itself. The enzyme REPRESSOR OF SILENCING 1 (ROS1) manages this process. The researchers used a molecular tool called XVE:ROS1 to control ROS1 activity precisely and study how plants establish, maintain, and erase immune memories.
The team found that plants can retain immune memory while protecting their DNA stability. After ROS1-triggered vaccination, plants temporarily redirect their DNA-silencing machinery away from defense genes and toward transposon-rich regions at chromosome centers, locking down "jumping genes" that could cause mutations. This preserves the genome while allowing defense genes in chromosome arms to retain their epigenetic memory.
Ton said the approach could generate epigenetic variation that alters how existing genes are regulated, rather than relying solely on DNA sequence differences as conventional crop breeding does. Collaboration with researchers at the Okinawa Institute of Science and Technology in Japan showed promising results in rice, with epigenetic memory partially transmitted to offspring across generations.
The Sheffield team is now refining the tool to create more stable epigenetic variation. Applications could extend beyond disease resistance to include tolerance to drought, heat, and salinity, as well as improvements to nutritional value and health-related compounds in vegetables.