Researchers may have discovered a previously unknown form of plant chatter that allows parasitic species and their hosts to share an astonishing amount of genetic information. The finding is exciting not only because it opens up an intriguing new field of research, but it could also lead to the development of novel strategies to tackle parasitic weeds that threaten food crops. The study has been published in Science.
It’s been known for some time that bits of information-containing material can shuffle between cells of a single plant. This material, which is called RNA, is produced from DNA and is used in the production of proteins. While this intercellular RNA movement has been studied extensively, scientists had not explored whether RNA transfer could occur between species until now.
For the present study, Virginia Tech researchers chose to investigate information sharing between a parasitic plant, dodder (C. pentagona), and two hosts- the model plant Arabidopsis and tomatoes. To find out what was being exchanged, the researchers sequenced the transcriptomes of the organisms. The transcriptome is the range of different RNA molecules expressed by an organism. Unlike an organism’s genome (DNA), the transcriptome actively changes depending on a variety of factors, such as environmental conditions.
The team was particularly interested in one type of RNA, called messenger RNA (mRNA), which acts as a template for protein synthesis. mRNA is often very unstable and readily broken down, so the researchers did not anticipate that it could easily transfer between species.
Much to their surprise, the scientists discovered that during this parasitic relationship, thousands of mRNAs were moved between the species in a bidirectional manner. These mobile transcripts represented thousands of different genes. Remarkably, almost half of Arabidopsis’s expressed transcriptome was found in the parasitic plant.
“The discovery of this novel form of inter-organism communication shows that this is happening a lot more than anyone has previously realized,” read researcher Jim Westwood said in a news-release. “Now that we have found they are sharing all this information, the next question is, ‘What exactly are they telling each other?’”
The researchers speculate that this molecular communication may allow the parasitic plant to influence the host, for example instructing it to dampen its defense responses so that it is more vulnerable to attack by the parasitic plant.
According to Sheffield University researcher Julie Scholes, who was not involved in the study, this finding could be very useful if researchers could use it to develop strategies that disrupt this flow of information. This could potentially help to control parasitic plants that wreak havoc in food crops.