Plant-insect interactions under bacterial influence: ecological implications and underlying mechanisms.
Plants and insects have been co-existing for more than 400 million years, leading to intimate and complex relationships. Throughout their own evolutionary history, plants and insects have also established intricate and very diverse relationships with microbial associates. Studies in recent years have revealed plant- or insect-associated microbes to be instrumental in plant-insect interactions, with important implications for plant defences and plant utilization by insects. Microbial communities associated with plants are rich in diversity, and their structure greatly differs between below- and above-ground levels. Microbial communities associated with insect herbivores generally present a lower diversity and can reside in different body parts of their hosts including bacteriocytes, haemolymph, gut, and salivary glands. Acquisition of microbial communities by vertical or horizontal transmission and possible genetic exchanges through lateral transfer could strongly impact on the host insect or plant fitness by conferring adaptations to new habitats. Recent developments in sequencing technologies and molecular tools have dramatically enhanced opportunities to characterize the microbial diversity associated with plants and insects and have unveiled some of the mechanisms by which symbionts modulate plant-insect interactions. Here, we focus on the diversity and ecological consequences of bacterial communities associated with plants and herbivorous insects. We also highlight the known mechanisms by which these microbes interfere with plant-insect interactions. Revealing such mechanisms in model systems under controlled environments but also in more natural ecological settings will help us to understand the evolution of complex multitrophic interactions in which plants, herbivorous insects, and micro-organisms are inserted.
INRA, Institut de Génétique, Environnement et Protection des Plantes, UMR 1349 IGEPP, Domaine de la Motte, 35653 Le Rheu Cedex, France akiko.sugio@rennes.inra.fr jean-christophe.simon@rennes.inra.fr.
Akiko
A
Sugio
Institut de Recherche sur la Biologie de l'Insecte, UMR 7261 CNRS / Université François-Rabelais, UFR Sciences et Techniques, Parc de Grandmont, 37200 Tours, France.
Géraldine
G
Dubreuil
Institut de Recherche sur la Biologie de l'Insecte, UMR 7261 CNRS / Université François-Rabelais, UFR Sciences et Techniques, Parc de Grandmont, 37200 Tours, France.
David
D
Giron
INRA, Institut de Génétique, Environnement et Protection des Plantes, UMR 1349 IGEPP, Domaine de la Motte, 35653 Le Rheu Cedex, France akiko.sugio@rennes.inra.fr jean-christophe.simon@rennes.inra.fr.
Jean-Christophe
JC
Simon
D000818:Animals; D001419:Bacteria / Q000378:metabolism*; D005075:Biological Evolution; D055669:Ecological and Environmental Phenomena; D060434:Herbivory; D006790:Host-Parasite Interactions / Q000502:physiology*; D007313:Insecta / Q000502:physiology*
herbivores; host–microbe interactions; microbial induced responses; plant defences; symbionts; trophic networks.