Evolutionary mechanisms underlying bacterial adaptation to the plant environment

Abstract Plants and bacteria have coevolved over hundreds of millions of years, forming complex associations ranging from mutualism to pathogenicity that are essential for plant survival and ecosystem function. Bacterial adaptation to plant environments involves dynamic evolutionary mechanisms including horizontal gene transfer, gene regulation, and metabolic specialization, enabling bacteria to persist and specialize within diverse plant-associated niches. Here we review how evolutionary forces such as selection, drift, and gene flow shape bacterial genomes, regulatory networks, and ecological strategies in response to plant-imposed pressures, underpinning both beneficial and pathogenic lifestyles. Understanding these processes provides a unified evolutionary framework for bacterial adaptation to plants and highlights their implications for sustainable agriculture and microbiome-based innovations.