Linking Phyllosphere and Rhizosphere Microbiome to the Plant-Insect Interplay: The New Dimension of Tripartite Interaction

Plants are constantly interacting with the diverse microbial community as well as insect pests throughout their life cycle. Due to their sessile nature, plants rely solely on the intracellular signaling and reprogramming of cellular events to resist against pathogens. Insect pests are usually dependent on the nutrient-rich fluid obtained from plants or directly consume plant parts to sustain their life cycle. Plants possess a plethora of microbial communities; these microbiomes constantly influence the physiology, growth, development, and immunity in plants. Hence, the phyllosphere and rhizosphere are believed to play a major role in plant-insect interaction. The phyllosphere, rhizosphere, and endosymbiotic microbiome are currently under extensive scientific investigation. Recently, the advancement of metagenomic next-generation sequencing (mNGS) platforms revolutionized plant-associated microbiome analysis and has unveiled many beneficial microbial communities protecting against diverse pathogenic microorganisms and insect pests. Mycorrhiza is also an important component of the rhizosphere, as it may play a role in soil microbiota, thus indirectly influencing the interaction of insects with plants. In this regard, the present review tries to focus on some major insect pests of plants, the molecular mechanism of plant-insect interaction, and the probable role of phyllosphere and rhizosphere microbiome in this plant-insect encounter. This review is believed to open up a new dimension in developing resistance in plants against insect pests.