It matters who you know, down below: Different mycorrhizal fungal communities differentially affect plant phenolic defences against herbivory

Abstract

ABSTRACTArbuscular mycorrhizal (AM) fungi are ubiquitous symbionts of most terrestrial plants. These fungi not only provide their host plants with access to nutrients and resources but are known to augment plant defences against insect herbivores. Relatively little is known about the role of AM fungal diversity and community assembly on the expression of plant defence traits. Here, we report how plant (Triticum aestivum) phenolic-based resistance to insect herbivory is differentially affected by different AM fungal communities. An inoculant of four AM fungal species and a field-sourced native AM fungal community increased plant phenolics by 47.9% and 50.2%, respectively, compared to plants inoculated with only one fungal species. Correspondingly, the performance (relative growth rate) of the insect herbivore was 36% and 61.3% lower when feeding on plants associated with these AM fungal communities. Furthermore, there was a negative correlation between foliar phenolics and herbivore growth. We propose that AM fungal community assembly can drive insect herbivore performance by affecting phenolic-based defence mechanisms.Competing Interest StatementThe authors have declared no competing interest.View Full Text