title: Cellular responses in the cyanobacterial symbiont during its vertical transfer between plant generations in the Azolla microphylla symbiosis.
abstract: The nitrogen-fixing symbiosis between cyanobacteria and the water fern Azolla microphylla is, in contrast to other cyanobacteria-plant symbioses, the only one of a perpetual nature. The cyanobacterium is vertically transmitted between the plant generations, via vegetative fragmentation of the host or sexually within megasporocarps. In the latter process, subsets of the cyanobacterial population living endophytically in the Azolla leaves function as inocula for the new plant generations. Using electron microscopy and immunogold-labeling, the fate of the cyanobacterium during colonization and development of the megasporocarp was revealed. On entering the indusium chamber of the megasporocarps as small-celled motile cyanobacterial filaments (hormogonia), these differentiated into large thick-walled akinetes (spores) in a synchronized manner. This process was accompanied by cytoplasmic reorganizations and the release of numerous membrane vesicles, most of which contained DNA, and the formation of a highly structured biofilm. Taken together the data revealed complex adaptations in the cyanobacterium during its transition between plant generations.
authors.affiliation: Key laboratory of Bio-Pesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, China, 350002;Biotechnology Institute, Fujian Academy of Agricultural Sciences, Fuzhou, China, 350003;Department of Botany, Stockholm University, SE-10691 Stockholm, Sweden.
authors.forename: Weiwen
authors.initials: W
authors.lastname: Zheng
authors.affiliation: Key laboratory of Bio-Pesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, China, 350002;Biotechnology Institute, Fujian Academy of Agricultural Sciences, Fuzhou, China, 350003;Department of Botany, Stockholm University, SE-10691 Stockholm, Sweden.
authors.forename: Birgitta
authors.initials: B
authors.lastname: Bergman
authors.affiliation: Key laboratory of Bio-Pesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, China, 350002;Biotechnology Institute, Fujian Academy of Agricultural Sciences, Fuzhou, China, 350003;Department of Botany, Stockholm University, SE-10691 Stockholm, Sweden.
authors.forename: Bin
authors.initials: B
authors.lastname: Chen
authors.affiliation: Key laboratory of Bio-Pesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, China, 350002;Biotechnology Institute, Fujian Academy of Agricultural Sciences, Fuzhou, China, 350003;Department of Botany, Stockholm University, SE-10691 Stockholm, Sweden.
authors.forename: Siping
authors.initials: S
authors.lastname: Zheng
authors.affiliation: Key laboratory of Bio-Pesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, China, 350002;Biotechnology Institute, Fujian Academy of Agricultural Sciences, Fuzhou, China, 350003;Department of Botany, Stockholm University, SE-10691 Stockholm, Sweden.
authors.forename: Guan
authors.initials: G
authors.lastname: Xiang
authors.affiliation: Key laboratory of Bio-Pesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, China, 350002;Biotechnology Institute, Fujian Academy of Agricultural Sciences, Fuzhou, China, 350003;Department of Botany, Stockholm University, SE-10691 Stockholm, Sweden.
authors.forename: Ulla
authors.initials: U
authors.lastname: Rasmussen
mesh_terms: D018441:Biofilms; D002454:Cell Differentiation; D021961:Cell Membrane Structures / Q000648:ultrastructure; D000458:Cyanobacteria / Q000502:physiology* / Q000648:ultrastructure; D029624:Ferns / Q000502:physiology* / Q000648:ultrastructure; D009586:Nitrogen Fixation / Q000502:physiology; D012098:Reproduction; D013559:Symbiosis / Q000502:physiology*