Mechanisms and Ecological Relevance of Direct Plant Responses to the Third Trophic Level

Informations projet

PRENEMA

N° de convention de subvention: 949595

DOI

10.3030/949595

Projet clôturé

Date de signature de la CE 22 Octobre 2020

Date de début 1 Janvier 2021

Date de fin 30 Juin 2026

Financé au titre de

• EXCELLENT SCIENCE - European Research Council (ERC)

Coût total

€ 1 499 671,00

Contribution de l’UE

€ 1 499 671,00

Coordonné par

UNIVERSITAET BERN
Switzerland

Periodic Reporting for period 3 - PRENEMA (Mechanisms and Ecological Relevance of Direct Plant Responses to the Third Trophic Level)

Période du rapport: 2024-01-01 au 2025-06-30

Résumé du contexte et des objectifs généraux du projet

Research shows that plants are able to sense the presence of predators and respond to them. The mechanisms of these responses, however, are largely unknown, including their influence on tritrophic interactions in nature. The EU-funded PRENEMA project will shed light on plant responses to the third trophic level – the natural enemies of herbivores – as a previously overlooked mechanism that controls tritrophic interactions. To do this, the project will use an interdisciplinary approach to the tritrophic model system consisting of maize and its wild ancestor teosinte, Diabrotica balteata – an insect that attacks maize roots – and its natural enemy, the nematode Heterorhabditis bacteriophora. PRENEMA's work can aid new approaches aimed at natural pest control in agriculture.

Travail effectué depuis le début du projet jusqu’à la fin de la période considérée dans le rapport et principaux résultats atteints jusqu’à présent

Just after mid-journey, PRENEMA advanced the technical and scientific frontiers forward as described below.

First, the PRENEMA team developed and validated of a new phenotyping platform (VolEx) that enables the simultaneous collection of root exudates and volatiles in a non-invasive manner. Using the VolEx system, we discovered that drought induced the exudation of multihexose benzoxazinoids. Because their production in plants and exact structure had previously not been fully elucidated, we isolated and characterized them through an extensive nuclear magnetic resonance study.

Second, the PRENEMA team is characterizing the plant response to entomopathogenic nematodes (EPNs). The biological responses observed were significantly more variable than initially anticipated, necessitating an increased focus on characterizing the plant exudation response to EPNs and the myriad factors influencing it. In particular, the team conducted an extensive literature review on the impact of biotic and abiotic parameters on the dynamics of plant exudation.

Moreover, as our understanding of the project's core themes has evolved, we have expanded our research scope to include additional, related aspects. These supplementary inquiries include the completion of a de novo assembly of the EPN, Heterorhabditis bacteriophora, genome and its annotation at a chromosome-scale, as well as the sequencing of 25 H. bacteriophora strains.

Third, we assessed whether the presence of EPNs in soil would affect multi trophic interactions in laboratory and field conditions. While EPNs did not affect belowground interactions, we observed that their presence in soil was sufficient to reduce the field populations of an insect pest, Ostrinia nubilalis. Further research is planned to identify the underlying mechanisms.

Overall, PRENEMA is to uncover nuanced insights into the intricate dynamics between plants and EPNs. We believe that PRENEMA will significantly contribute to the field, offering a more detailed and comprehensive understanding of tritrophic interactions.

Progrès au-delà de l’état des connaissances et impact potentiel prévu (y compris l’impact socio-économique et les conséquences sociétales plus larges du projet jusqu’à présent)

The newly developed root exometabolome sampling system (VolEx) is an important technological step forward in the field, as no other methods were available to collect both volatile and non-volatile metabolites so far. By the end of the project, we expect to have thoroughly characterized the plant responses to entomopathogenic nematodes, their mechanisms, and relevance in agroecosystems.

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