HerbivoreAssociatedOrganisms · Unravelling the complexity of plant-insect interactions: the hidden role played by herbivore-associated-organisms

Unravelling the complexity of plant-insect interactions: the hidden role played by herbivore-associated-organisms

Plants interact with a suite of different organisms in nature, including herbivorous and carnivorous insects. It is now recognized that plants are not alone when interacting with other organisms because hidden players may modulate the strength of plant-insect interactions. In particular, there is growing evidence on the effects of microbial symbionts in plant responses towards herbivory. Plant-associated symbionts such as mycorrhizal fungi affect not only plant growth but also plant defences by inducing systemic resistance towards a wide range of attackers including aboveground herbivores. Herbivore-associated symbionts such as bacteria present in oral secretions can manipulate the physiology of plants to the benefit of their herbivore hosts. Carnivorous insects can also harbour symbionts but their role has not been investigated in a plant-insect perspective. Among carnivorous insects, parasitoids are a common group of insects whose larvae develop at the expense of the herbivorous host eventually killing it. It has been shown that parasitoids alter the physiology of their herbivorous host, and this in turn changes the way the herbivore interacts with the plant with consequences for species interactions across multiple trophic levels. The effect of parasitization of herbivores on plant responses has been assumed to be triggered by the parasitic wasp larvae feeding within the herbivore’s body. However, thousands of parasitoid species inject specific symbiotic viruses (polydnaviruses) into their hosts that manipulate herbivore physiology and immune responses. During oviposition, parasitoids also inject venoms which may synergize the effects of polydnaviruses and can be required for expression of viral genes in the caterpillar. To unravel the role of parasitoid symbionts at the plant-insect interface and to raise awareness on the importance of these interactions, the HerbivoreAssociatedOrganisms project has developed several scientific objectives, training activities and dissemination practices. The first main research objective of this project was to explore whether parasitoid symbionts injected in the caterpillar affect plant phenotype to the extent that it influences the behaviour of other insect community members associated with the same plant. The second main research objective of this project was to investigate the molecular mechanisms underlying the ecology of plant-herbivore interactions induced by parasitoid symbionts. We concluded that parasitoid symbionts affect plant-insect interactions at different levels of biological organization, from plant gene expression to consequences for the wider plant-associated insect community.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз