Comparative genome analysis of Burkholderia phytofirmans PsJN reveals a wide spectrum of endophytic lifestyles based on interaction strategies with host plants

Burkholdena phytohanans PsJN is a naturally occurring plant-associated bacterial endophyte that effectively colonizes a wide range of plants and stimulates their growth and vitality. Here we analyze whole genomes, of PsJN and of eight other endophytic bacteria. This study illustrates that a wide spectrum of endophytio life styles exists. Although we postulate the existence of typical endophytic traits, no unique gene cluster could be exclusively linked to the endophytic lifestyle. Furthermore, our study revealed a high genetic diversity among bacterial endophytes as reflected in their genotypic and phenotypic features. B. phytofirrnans PsJN is in many aspects outstanding among the selected endophytes. It has the biggest genome consisting of two chromosomes and one plasmid, well-equipped with genes for the degradation of complex organic compounds and detoxification, e.g., 24 glutathione-S-transferase (GST) genes. Furthermore, strain PsJN has a high number of cell surface signaling and secretion systems and harbors the 3-OH-PAME quorum sensing system that coordinates the switch of free-living to the symbiotic lifestyle in the plant-pathogen B. solanacearum. The ability of B. phytofirmans PsJN to successfully colonize such a wide variety of plant species might be based on its large genome harboring a broad range of physiological functions. EWE (National Science Foundation) [P22867-B16, P21261-1303] US DOE's Office of Science, Biological, and Environmental Research Program [DE-AC02-05CH11231] We thank Jim Tiedje and Alban Ramette for encouragement and the initiative to sequence the genome of strain PsJN. This work was supported by grants provided by the EWE (National Science Foundation, grant no P22867-B16 and P21261-1303). The sequencing for the project was provided through the US Department of Energy (DOE) Sequencing Program (http:// www.jgi.doe.gov/CSP/index.html). This work was performed at Lawrence Berkeley National Laboratory, Lawrence Livermore National Laboratory, and Los Alamos National Laboratory, under the auspices of the US DOE's Office of Science, Biological, and Environmental Research Program under contract no. DE-AC02-05CH11231.