Green plants, or Viridiplantae, are foundational to the ecosystems on Earth and play essential roles in climate and ecosystem changes. Understanding the evolution of green plants remains a major challenge in evolutionary biology. Recent advancements in genomics have sequenced more than a thousand plant genomes, paving the way to explore genomic changes along the evolution of plants and uncover the molecular basis behind their diverse biological innovations. For a long time, great attention has been paid to gene gain over gene loss. This project aims to shift that focus, testing the hypothesis that gene loss plays a crucial role in shaping plant adaptation, speciation, and biological innovations. To this end, this project will develop a novel genomic approach integrating homolog identification and multiple genome alignment to identify gene loss in plants and investigate its links with species divergence and adaptive traits in various plant clades. Further exploring the functional and evolutionary consequences of lost genes would shed light on the evolutionary significance of gene loss in plants. With this focus, the project not only deepens our understanding of plant evolution but also examines the paradoxical concept that sometimes less can be more in evolution.