摘要How horizontal gene transfer(HGT)has contributed to the evolution of animals and plants remains a major puzzle.Despite recent progress,defining the overall scale and pattern of HGT events in land plants has been largely elusive.In this study,we performed systematic analyses for acquired genes in different plant groups and throughout land plant evolution.We found that relatively recent HGT events occurred in char-ophytes and all major land plant groups,but their frequency declined rapidly in seed plants.Two major ep-isodes of HGT events occurred in land plant evolution,corresponding to the early evolution of strepto-phytes and the origin of land plants,respectively.Importantly,a vast majority of the genes acquired in the two episodes have been retained in descendant groups,affecting numerous activities and processes of land plants.We analyzed some of the acquired genes involved in stress responses,ion and metabolite transport,growth and development,and specialized metabolism,and further assessed the cumulative ef-fects of HGT in land plants.