Microbial interactions within the plant holobiont are critical for shaping plant-associated microbial communities and influencing plant health. Plants and their associated microbes form a complex assemblage known as a holobiont, where both host and microbial interactions drive evolutionary selection. Microbe-microbe interactions, particularly among prokaryotes and micro-eukaryotes, play a fundamental role in determining microbial community structure and plant fitness. These interactions include cooperation, competition, and other mechanisms that influence the establishment and maintenance of host-microbial homeostasis. Plant-associated microbial communities consist of bacteria, fungi, and protists, with bacteria dominating in both above- and belowground tissues. Fungal communities are also diverse, with Ascomycota and Basidiomycota being the main phyla. Protists, particularly Oomycota and Cercozoa, are also important components of the plant microbiota, though they are often overlooked. These microbes interact with each other and with the plant host, influencing plant growth, health, and resistance to pathogens. Microbial interactions include nutritional interdependencies, biofilm formation, molecular communication, enhanced dispersal, bacterial endosymbiosis, and competitive interactions. These mechanisms allow microbes to cooperate, compete, and adapt to their environment. For example, biofilm formation provides protection and enhances microbial survival, while quorum sensing allows microbes to communicate and coordinate activities. Competitive interactions, such as resource competition and contact-dependent killing, help shape microbial communities and influence plant health. Microbial hubs, or keystone species, play a critical role in structuring plant-associated microbial communities. These species are highly connected within the network and can significantly influence microbial community composition and function. The interactions between microbes and the plant host are essential for maintaining plant health and promoting growth. Understanding these interactions is crucial for developing strategies to enhance plant productivity and resilience to environmental stresses. The study of microbial interactions in the plant holobiont provides insights into the complex relationships that shape plant-associated microbial communities and their impact on plant health.Microbial interactions within the plant holobiont are critical for shaping plant-associated microbial communities and influencing plant health. Plants and their associated microbes form a complex assemblage known as a holobiont, where both host and microbial interactions drive evolutionary selection. Microbe-microbe interactions, particularly among prokaryotes and micro-eukaryotes, play a fundamental role in determining microbial community structure and plant fitness. These interactions include cooperation, competition, and other mechanisms that influence the establishment and maintenance of host-microbial homeostasis. Plant-associated microbial communities consist of bacteria, fungi, and protists, with bacteria dominating in both above- and belowground tissues. Fungal communities are also diverse, with Ascomycota and Basidiomycota being the main phyla. Protists, particularly Oomycota and Cercozoa, are also important components of the plant microbiota, though they are often overlooked. These microbes interact with each other and with the plant host, influencing plant growth, health, and resistance to pathogens. Microbial interactions include nutritional interdependencies, biofilm formation, molecular communication, enhanced dispersal, bacterial endosymbiosis, and competitive interactions. These mechanisms allow microbes to cooperate, compete, and adapt to their environment. For example, biofilm formation provides protection and enhances microbial survival, while quorum sensing allows microbes to communicate and coordinate activities. Competitive interactions, such as resource competition and contact-dependent killing, help shape microbial communities and influence plant health. Microbial hubs, or keystone species, play a critical role in structuring plant-associated microbial communities. These species are highly connected within the network and can significantly influence microbial community composition and function. The interactions between microbes and the plant host are essential for maintaining plant health and promoting growth. Understanding these interactions is crucial for developing strategies to enhance plant productivity and resilience to environmental stresses. The study of microbial interactions in the plant holobiont provides insights into the complex relationships that shape plant-associated microbial communities and their impact on plant health.