Biologists have discovered that the surfaces of plant leaves are covered with a wide variety of RNA molecules. This discovery indicates that the RNA found on leaf surfaces may influence the microbial communities living there, which could, in turn, affect plant health and their environmental interactions, as highlighted in a recent study.
Biologists at Indiana University Bloomington have revealed that plant leaf surfaces are coated with a diverse assortment of RNA molecules. This finding implies that the RNA on these surfaces might play a significant role in shaping the microbial communities that reside there, potentially impacting plant health and their interactions with the environment, according to a new study.
The research titled, Diverse plant RNAs coat Arabidopsis leaves and are distinct from apoplastic RNAs, was published on January 3, 2025, in the Proceedings of the National Academy of Sciences. The principal authors, Lucía Borniego and Meenu Singla-Rastogi, are postdoctoral researchers in the Department of Biology at Indiana University. The senior author is Roger Innes, a Distinguished Professor of Biology.
“What thrills us the most about this discovery is that it suggests plants might be able to control their microbiomes by regulating gene expression in microbes through cross-kingdom RNA interference, often referred to as RNAi,” stated Innes. “RNA interference is a well-recognized method of gene regulation where cells can reduce the expression of a gene by producing a small RNA that can pair with the RNA of the target gene. This gene regulation mechanism seems to exist in nearly all living organisms, but it has only recently been shown that RNAs from one organism can be absorbed by another and interact with their RNAs.”
RNA is highly delicate and is quickly degraded unless it is safeguarded. This study provides some of the initial evidence that plants can release functional RNA onto the surfaces of their leaves.
The research indicates that there are significant amounts of RNA on leaf surfaces that are unexpectedly stable. The findings suggest that this stability may relate to the RNA’s ability to form condensates with polysaccharides like pectin. By identifying that plant leaves are covered with RNA, this study implies that the microbes colonizing these leaf surfaces are exposed to plant RNA and are likely to interact with it. This interaction could influence gene expression in these microbes, thus affecting which microbes flourish on the leaves.
“The influence of environmental RNA on microbial communities is probably happening in our own intestines as well, with RNA being secreted by our intestinal epithelial cells,” Innes remarked. “It’s also quite likely that RNA on the surfaces of leaves, such as in salad, could impact our own gut microbiomes.”
Other contributors to the paper include Megha Hastantram Sampangi-Ramaiah and Hana Zand Karimi from the Department of Biology at Indiana University, Patricia Baldrich and Blake C. Meyers from the University of California — Davis, and Madison McGregor from the Donald Danforth Plant Science Center.
