Trees and Insects Have Microbiomes: Consequences for Forest Health and Management

Abstract

Purpose of reviewForest research has shown for a long time that microorganisms influence tree-insect interactions, but the complexity of microbial communities, as well as the holobiont nature of both trees and insect herbivores, have only recently been taken fully into account by forest entomologists and ecologists. In this article, we review recent findings on the effects of tree-insect-microbiome interactions on the health of tree individuals and discuss whether and how knowledge about tree and insect microbiomes could be integrated into forest health management strategies. We then examine the effects tree-insect-microbiome interactions on forest biodiversity and regeneration, highlighting gaps in our knowledge at the ecosystem scale. Recent findingsMultiple studies show that herbivore damage in forest ecosystems is clearly influenced by tripartite interactions between trees, insects and their microbiomes. Recent research on the plant microbiome indicates that microbiomes of planted trees could be managed at several stages of production, from seed orchards to mature forests, to improve the resistance of forest plantations to insect pests. Therefore, the tree microbiome could potentially be fully integrated into forest health management strategies.

Exchange of Microbiomes in Plant-Insect Herbivore Interactions

“…The next step could be manipulations of the microbiome exchange. This could take place through the enrichment of species of bacteria or fungi that are beneficial for the plant in that they enhance plant growth, kill pathogens or pests ( 133 ), or eliminate plant-pathogenic strains through, for example, phage-based strategies ( 134 , 135 ). The microbial biocontrol of herbivores would provide an environmentally friendly alternative to chemical pesticides that are, to a great extent, responsible for the global insect decline ( 17 , 135 – 139 ).…”

Insights into the Role of Fungi in Pine Wilt Disease

“…Plant microbiome is considered a very propitious strategy for fostering plant protection against abiotic and biotic stressors [92]. Research on PWD-associated mycoflora has been slowly progressing since the first studies in the mid-seventies.…”

Microbial biomarkers of tree water status for next‐generation biomonitoring of forest ecosystems

“…Our vision of the implementation of next‐generation biomonitoring for forest ecosystems relies on the diversified communities of microorganisms that constitute the microbiota of all plant and tree species. The plant microbiota includes some microbial species that promote plant growth (Compant et al, 2010; Hardoim et al, 2015), and contribute to plant resistance to microbial pathogens (Hacquard et al, 2017; Hacquard & Schadt, 2015; McLaren & Callahan, 2020; Vannier et al, 2019) and insect pests (Pineda et al, 2017; Vacher et al, 2021), and to the tolerance to abiotic stressors including drought (Lata et al, 2018; Rho et al, 2018; Rodriguez et al, 2008). In addition to contributing to plant response to environmental stressors, plant‐associated microbial communities respond rapidly to environmental change.…”