The effect of Rare Earth Elements (REEs) on plants shapes multiple trophic interactions in the agroeCOsystems

Rare Earth Elements (REEs) play a crucial role in our life because of their broad range of applications, running from industrial production, for example in mobile phones, to agriculture, where they serve as fertilizers. Because of their broad spectrum of applications in agriculture and industry, there is increasing evidence that REEs concentrations are building up in natural environments. This accumulation of REEs in the environment may have drastic effects on ecosystem diversity and functioning. Whereas the biological impact of low levels of REEs on plant growth has been well documented, the effect of high levels of REEs and the ecological impact on higher trophic levels are still unknown. Here, I assume that accumulated high levels of REEs affect plants differently than the levels currently applied in agriculture. Moreover, these effects are likely to cascade up to higher tropic levels associated with plants, such as root/leaf herbivores and natural enemies. My research aims to invest how the impact of the Rare Earth Elements on the eCOsystem (RECO) by assessing the impact of the Rare Earth Element on multitrophic interactions among plants, herbivores (below and above ground herbivore), and their natural enemies (below and aboveground). In this research proposal, Lanthanum (La) and Cerium (Ce) are chosen as REE elements. Hereby I consider the impact of series levels of La and Ce on Brassica plants, herbivores, and natural enemies interactions. My aim is to: (1) Determine the impact of La and Ce on Brassica rapa performance as well as its metabolome; (2) Assess the effect of La and Ce on plant defense to the belowground herbivore Delia radicum and aboveground herbivore Spodoptera exigua; (3) Assess the impact of La and Ce on the attraction and efficacy of entomopathogenic nematodes Heterorhabditis bacteriophora and parasitoid wasp Cotesia marginiventris.