title: Movement of rhizobia inside tobacco and lifestyle alternation from endophytes to free-living rhizobia on leaves.
abstract: Rhizobia are well-known for their ability to infect and nodulate legume roots, forming a nitrogen-fixing symbiosis of agricultural importance. In addition, recent studies have shown that rhizobia can colonize roots and aerial plant tissues of rice as a model plant of the Graminaceae family. Here we show that rhizobia can invade tobacco, a model plant belonging to the Solanaceae family. Inoculation of seedling roots with five GFP-tagged rhizobial species followed by microscopy and viable plating analyses indicated their colonization of the surface and interior of the whole vegetative plant. Blockage of ascending epiphytic migration by coating the hypocotyls with Vaseline showed that the endophytic rhizobia can exit the leaf interior through stomata and colonize the external phyllosphere habitat. These studies indicate rhizobia can colonize both below and above-ground tissues of tobacco using a dynamic invasion process that involves both epiphytic and endophytic lifestyles.
authors.affiliation: Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 10093, China.
authors.forename: Kui-Xian
authors.initials: KX
authors.lastname: Ji
authors.forename: Feng
authors.initials: F
authors.lastname: Chi
authors.forename: Ming-Feng
authors.initials: MF
authors.lastname: Yang
authors.forename: Shi-Hua
authors.initials: SH
authors.lastname: Shen
authors.forename: Yu-Xiang
authors.initials: YX
authors.lastname: Jing
authors.forename: Frank B
authors.initials: FB
authors.lastname: Dazzo
authors.forename: Hai-Ping
authors.initials: HP
authors.lastname: Cheng
mesh_terms: D018515:Plant Leaves / Q000382:microbiology; D012231:Rhizobium / Q000254:growth & development / Q000502:physiology*; D014026:Nicotiana / Q000382:microbiology*