Friend or foe? The role of leaf-inhabiting fungal pathogens and endophytes in tree-insect interactions

摘要

Trees are large organisms that structure forest ecosystems by providing an environment for an enormous diversity of animal, microbial and plant species. As these species use trees as their common hosts, many are likely to interact with each other directly or indirectly. From studies on herbaceous plant species we know that microbes can affect the interaction of plants with herbivorous insects, for example via changes in plant metabolite profiles. The consequences of fungal colonization for tree-insect interactions are, however, barely known, despite the importance of these ecological communities. In this review we explore the interaction of leaf-inhabiting pathogenic and endophytic fungi with trees and the consequences for tree-living insect herbivores. We discuss molecular, physiological, chemical, biochemical and ecological aspects of tree-fungus interactions and summarize the current knowledge on the direct and indirect effects of tree-inhabiting fungi on insect herbivores.