Jim Westwood, professor of plant pathology and physiology at Virginia Tech in the US, has found that plants ‘talk’ to each other on a molecular level, swapping DNA information in a way that parasitic plants might be taking advantage of.
Westwood made this discovery by looking at the interactions between a parasitic plant called a dodder, and two types of host plants - a small flowering plant called an Arabidopsis, and a tomato plant. Also known as Cuscuta plants, dodders use a creeping appendage called a haustorium to penetrate their host plants and feed on their nutrients. In previous studies, Westwood had discovered that during this interaction, RNA molecules - which play a crucial role in coding, decoding, regulating, and expressing information passed down from DNA - were being passed between the two species.
More recently, Westwood looked into the possibility that a special type of RNA molecules - mRNA, or messenger RNA - were also being transported between the parasitic and host plants. Messenger RNA molecules send messages within cells, instructing them on which actions to take and when.
"It was thought that mRNA was very fragile and short-lived, so transferring it between species was unimaginable,” Phys.org reports. "But Westwood found that during this parasitic relationship, thousands upon thousands of mRNA molecules were being exchanged between both plants, creating this open dialogue between the species that allows them to freely communicate.”
Here’s where it gets a bit sinister, because through this exchange of messenger RNA molecules, the parasitic dodder plant could be instructing the host plants on what to do, such as lowering their defences so the dodder can attack them with less resistance. Westwood plans to find this out in the next stage of his research.
"The discovery of this novel form of inter-organism communication shows that this is happening a lot more than any one has previously realised," said Westwood in a press release. "Now that we have found that they are sharing all this information, the next question is, 'What exactly are they telling each other?’.”
Other than giving us a much deeper insight into the behaviour of plants, this information could help scientists come up with better solutions to fight the parasitic weeds that threaten food crops in developing countries around the world.
"Parasitic plants such as witchweed and broomrape are serious problems for legumes and other crops that help feed some of the poorest regions in Africa and elsewhere," Julie Scholes, a professor at the University of Sheffield in UK who was not part of this project, said in the press release. "In addition to shedding new light on host-parasite communication, Westwood's findings have exciting implications for the design of novel control strategies based on disrupting the mRNA information that the parasite uses to reprogram the host.”
"The beauty of this discovery is that this mRNA could be the Achilles hill for parasites," Westwood added. "This is all really exciting because there are so many potential implications surrounding this new information."
Westwood’s research was published today in the journal Science.