Pathways of DNA Transfer to Plants from and Related Bacterial Species.

Genetic transformation of host plants by and related species represents a unique model for natural horizontal gene transfer. Almost five decades of studying the molecular interactions between and its host cells have yielded countless fundamental insights into bacterial and plant biology, even though several steps of the DNA transfer process remain poorly understood. spp. may utilize different pathways for transferring DNA, which likely reflects the very wide host range of . Furthermore, closely related bacterial species, such as rhizobia, are able to transfer DNA to host plant cells when they are provided with DNA transfer machinery and T-DNA. Homologs of virulence genes are found in many bacterial genomes, but only one non- bacterial strain, CFN42, harbors a complete set of virulence genes and can mediate plant genetic transformation when carrying a T-DNA-containing plasmid.