Plants speak to their friends but are eavesdropped by their enemies
The Netherlands Organisation for Scientific Research (NWO) has awarded a Vici grant to Harro Bouwmeester, a researcher at Plant Research International, an institute of Wageningen UR. Bouwmeester was acclaimed for his research on the subterranean communication of plants. Plants send out chemical signals to facilitate the colonisation of their roots by beneficial mycorrhizal fungi, but these signals are abused by parasitic plants to find their host. The Vici grant, awarded for groundbreaking research, can amount to up to € 1,250,000 and is intended to facilitate the establishment of a research group.
Photo: Tomato infected by Orobanche ramosa
Although plants cannot talk, they communicate extensively with eachother and with other organisms. For example, plants that are being attacked by insects emit volatiles that attract the natural enemies of these insects. The plant calls for help, as it were.
Bouwmeester has long been fascinated by communication among plants. He is one of the authors of an article recently published in the renowned journal Science, which describes the communication research carried out by Wageningen University and Plant Research International. In this study, plants of Arabidopsis thaliana (Thale Cress or Mouse-ear Cress) were equipped with a strawberry gene via genetic modification. The genetically modified Arabidopsis plants emitted new volatiles that were attractive to predatory mites the natural enemy of the harmful spider mite.
Bouwmeester was awarded the Vici grant for his proposal to investigate the communication in the triangular relationship of host plant/parasitic plant/mycorrhizal fungus. Parasitic plants need a host plant to survive and use their host as a source of water, minerals and assimilates, often completely exhausting it in the process. In many African countries, parasitic plants cause catastrophic harvest losses. Bouwmeester hopes that his research will not only improve our understanding of how parasitic plants and hosts communicate but will also help in alleviating this huge problem in Africa. What is already known is that the parasitic plant recognises its host through the secretion of chemical compounds by the roots of the host. A relevant question here is why the host communicates with the parasite in the first place.
Bouwmeester’s idea is that this is connected to the mycorrhizal fungi. Mycorrhizal fungi live in symbiosis with plants, meaning that both profit from the interaction – the plant supplies the fungus with energy from its photosynthetic process, while the fungus transmits minerals from the soil to the plant. Bouwmeester suspects that the communication between the plant and the benign mycorrhizal fungus has been hijacked by the parasitic plants.
His research will focus on how the host produces the signalling molecules, how these molecules function in underground communication between the three organisms and how the parasitic plants have evolved the ability to perceive these signals. Earlier results have indicated that the communication between host and parasite is extremely sensitive – no more than a few molecules of the relevant compounds are enough to identify a host.
NWO has also awarded Veni grants (for young, newly graduated scientists with exceptional and original talent for carrying out innovative scientific research) to two staff at Wageningen University, Plant Sciences.
Ties Huigens from the Entomology group was awarded a Veni grant for his research on the use by Trichogramma wasps of the anti-sex scent of butterflies. Male butterflies frequently transfer scents to their partners, which repel male competitors. Anti-sex scents can also attract natural enemies, however. Huigens will investigate the degree to which parasitic wasps exploit the anti-sex scents of Cabbage White butterflies.
Erik Limpens from the Molecular Biology group received a Veni grant for his research into bacteria as guest workers in plant cells. Nitrogen-fixing Rhizobium bacteria are located within specially formed cells of legumes such as pea and soybean. Here they convert air into building blocks for the plant. Limpens intends to study how these bacteria are assimilated in the plant cells.