This article explores how abiotic and host factors, along with microbial interactions, shape the plant microbiome, focusing on the phyllosphere of *Arabidopsis thaliana*. The study identifies "microbial hubs" – key microorganisms that significantly influence community structure through interactions with other microbes. These hubs, such as the oomycete pathogen *Albugo* and the basidiomycete *Dioszegia*, play critical roles in determining microbial diversity and colonization patterns. The research shows that abiotic factors, host genotype, and microbial interactions collectively affect the phyllosphere microbiome. *Albugo* was found to suppress bacterial diversity and stabilize community structure, while *Dioszegia* interacts directly with phyllosphere bacteria. The study highlights the importance of microbial hubs in mediating the effects of environmental and host factors on microbial communities. By analyzing interactions between these hubs and other microbes, the research provides insights into how host and environmental factors influence microbial communities, with implications for understanding plant-microbe interactions and developing strategies for managing plant health. The findings underscore the complex interplay between microbes, their interactions, and the host environment in shaping the plant microbiome.This article explores how abiotic and host factors, along with microbial interactions, shape the plant microbiome, focusing on the phyllosphere of *Arabidopsis thaliana*. The study identifies "microbial hubs" – key microorganisms that significantly influence community structure through interactions with other microbes. These hubs, such as the oomycete pathogen *Albugo* and the basidiomycete *Dioszegia*, play critical roles in determining microbial diversity and colonization patterns. The research shows that abiotic factors, host genotype, and microbial interactions collectively affect the phyllosphere microbiome. *Albugo* was found to suppress bacterial diversity and stabilize community structure, while *Dioszegia* interacts directly with phyllosphere bacteria. The study highlights the importance of microbial hubs in mediating the effects of environmental and host factors on microbial communities. By analyzing interactions between these hubs and other microbes, the research provides insights into how host and environmental factors influence microbial communities, with implications for understanding plant-microbe interactions and developing strategies for managing plant health. The findings underscore the complex interplay between microbes, their interactions, and the host environment in shaping the plant microbiome.