The concept of the plant holobiont, which includes the plant and its associated microbial communities, has gained significant attention in recent microbiome research. This concept, rooted in the idea of shared governance between the host and its microbiota, highlights the ecological and genetic features that underpin mutualistic relationships. The plant holobiont is crucial for understanding the impacts of global environmental changes, particularly in the context of one health and planetary health. The integration of plant holobionts into broader holobiome and one health frameworks reveals knowledge gaps that require further investigation. The evolution of plant holobionts has been influenced by ancient microbial interactions, including symbiotic relationships with mycorrhizal fungi and bacteria. These interactions have shaped plant development, growth, and adaptation to environmental stressors. The microbiome of plants, which includes a diverse array of microbial cells from various domains of life, plays a vital role in plant health, influencing growth, productivity, and resistance to biotic and abiotic stresses. The microbiome is transmitted vertically through seeds and horizontally through the environment, with both mechanisms contributing to the survival and adaptation of plant species. Climate change poses significant challenges to plant holobionts, affecting microbial diversity, community composition, and ecosystem functioning. The SPRUCE experiment demonstrated that warming and elevated CO₂ levels can disrupt the balance of the Sphagnum microbiome, leading to dysbiosis and altered carbon and nitrogen cycles. These changes have implications for carbon storage, methane emissions, and the overall health of peatland ecosystems. The plant holobiont is also relevant to human health, as plant-associated microbes can act as reservoirs for pathogens, including those that cause healthcare-associated infections. The increasing prevalence of antimicrobial resistance in plant-associated microbes underscores the need for microbiome-based approaches to disease prevention and control. The integration of plant holobionts into the one health framework highlights the interconnectedness of human, animal, and environmental health. In conclusion, the study of plant holobionts provides insights into the coevolution of plants and their microbiomes, the shared governance between hosts and microbes, and the implications for one health and planetary health. Future research should focus on understanding the functional implications of shared governance, the role of plant holobionts in global ecosystems, and the development of microbiome-based strategies for sustainable agriculture and disease prevention.The concept of the plant holobiont, which includes the plant and its associated microbial communities, has gained significant attention in recent microbiome research. This concept, rooted in the idea of shared governance between the host and its microbiota, highlights the ecological and genetic features that underpin mutualistic relationships. The plant holobiont is crucial for understanding the impacts of global environmental changes, particularly in the context of one health and planetary health. The integration of plant holobionts into broader holobiome and one health frameworks reveals knowledge gaps that require further investigation. The evolution of plant holobionts has been influenced by ancient microbial interactions, including symbiotic relationships with mycorrhizal fungi and bacteria. These interactions have shaped plant development, growth, and adaptation to environmental stressors. The microbiome of plants, which includes a diverse array of microbial cells from various domains of life, plays a vital role in plant health, influencing growth, productivity, and resistance to biotic and abiotic stresses. The microbiome is transmitted vertically through seeds and horizontally through the environment, with both mechanisms contributing to the survival and adaptation of plant species. Climate change poses significant challenges to plant holobionts, affecting microbial diversity, community composition, and ecosystem functioning. The SPRUCE experiment demonstrated that warming and elevated CO₂ levels can disrupt the balance of the Sphagnum microbiome, leading to dysbiosis and altered carbon and nitrogen cycles. These changes have implications for carbon storage, methane emissions, and the overall health of peatland ecosystems. The plant holobiont is also relevant to human health, as plant-associated microbes can act as reservoirs for pathogens, including those that cause healthcare-associated infections. The increasing prevalence of antimicrobial resistance in plant-associated microbes underscores the need for microbiome-based approaches to disease prevention and control. The integration of plant holobionts into the one health framework highlights the interconnectedness of human, animal, and environmental health. In conclusion, the study of plant holobionts provides insights into the coevolution of plants and their microbiomes, the shared governance between hosts and microbes, and the implications for one health and planetary health. Future research should focus on understanding the functional implications of shared governance, the role of plant holobionts in global ecosystems, and the development of microbiome-based strategies for sustainable agriculture and disease prevention.