Regulation of photosynthesis during heterocyst differentiation in Anabaena sp strain PCC 7120 investigated in vivo at single-cell level by chlorophyll fluorescence kinetic microscopy

0422189 - MBÚ 2014 RIV NL eng J - Journal Article
Ferimazová, Naila - Felcmanová, Kristina - Šetlíková, Eva - Küpper, H. - Maldener, I. - Hauska, G. - Šedivá, Barbora - Prášil, Ondřej
Regulation of photosynthesis during heterocyst differentiation in Anabaena sp strain PCC 7120 investigated in vivo at single-cell level by chlorophyll fluorescence kinetic microscopy.
Photosynthesis Research. Roč. 116, č. 1 (2013), s. 79-91. ISSN 0166-8595. E-ISSN 1573-5079
R&D Projects: GA ČR GA206/08/1683; GA MŠMT(CZ) ED2.1.00/03.0110
Institutional support: RVO:61388971
Keywords : Acclimation to abiotic stress * Heterocyst differentiation * Nitrogen fixation
Subject RIV: EE - Microbiology, Virology
Impact factor: 3.185, year: 2013

Changes of photosynthetic activity in vivo of individual heterocysts and vegetative cells in the diazotrophic cyanobacterium Anabaena sp. strain PCC 7120 during the course of diazotrophic acclimation were determined using fluorescence kinetic microscopy (FKM). Distinct phases of stress and acclimation following nitrogen step-down were observed. The first was a period of perception, in which the cells used their internally stored nitrogen without detectable loss of PS II activity or pigments. In the second, the stress phase of nitrogen limitation, the cell differentiation occurred and an abrupt decline of fluorescence yield was observed. This decline in fluorescence was not paralleled by a corresponding decline in photosynthetic pigment content and PS II activity. Both maximal quantum yield and sustained electron flow were not altered in vegetative cells, only in the forming heterocysts. The third, acclimation phase started first in the differentiating heterocysts with a recovery of PS II photochemical yields Afterwards, the onset of nitrogenase activity was observed, followed by the restoration of antenna pigments in the vegetative cells, but not in the heterocysts. Surprisingly, mature heterocysts were found to have an intact PS II as judged by photochemical yields, but a strongly reduced PS II-associated antenna as judged by decreased F (0). The possible importance of the functional PS II in heterocysts is discussed
Permanent Link: http://hdl.handle.net/11104/0228423