title: Relationship Between Photochemical Quenching and Non-Photochemical Quenching in Six Species of Cyanobacteria Reveals Species Difference in Redox State and Species Commonality in Energy Dissipation.
abstract: Although the photosynthetic reaction center is well conserved among different cyanobacterial species, the modes of metabolism, e.g. respiratory, nitrogen and carbon metabolism and their mutual interaction, are quite diverse. To explore such uniformity and diversity among cyanobacteria, here we compare the influence of the light environment on the condition of photosynthetic electron transport through Chl fluorescence measurement of six cyanobacterial species grown under the same photon flux densities and at the same temperature. In the dark or under weak light, up to growth light, a large difference in the plastoquinone (PQ) redox condition was observed among different cyanobacterial species. The observed difference indicates that the degree of interaction between respiratory electron transfer and photosynthetic electron transfer differs among different cyanobacterial species. The variation could not be ascribed to the phylogenetic differences but possibly to the light environment of the original habitat. On the other hand, changes in the redox condition of PQ were essentially identical among different species at photon flux densities higher than the growth light. We further analyzed the response to high light by using a typical energy allocation model and found that 'non-regulated' thermal dissipation was increased under high-light conditions in all cyanobacterial species tested. We assume that such 'non-regulated' thermal dissipation may be an important 'regulatory' mechanism in the acclimation of cyanobacterial cells to high-light conditions.
authors.affiliation: Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480 Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Misumi
authors.affiliation: Division of Plant Functional Genomics, Life Science Research Center, Mie University, Kurimamachiya 1577, Tsu, Mie, 514-8507 Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Katoh
authors.affiliation: Department of Biology, Faculty of Science, Tokyo University of Science, Kagurazaka 1-3, Shinjuku-Ku, Tokyo, 162-8601 Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Tomo
authors.affiliation: Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480 Japan sonoike@waseda.jp.
authors.forename: Kintake
authors.initials: K
authors.lastname: Sonoike
mesh_terms: D002734:Chlorophyll / Q000378:metabolism; D000458:Cyanobacteria / Q000378:metabolism*; D005453:Fluorescence; D007700:Kinetics; D010084:Oxidation-Reduction; D055668:Photochemical Processes; D010788:Photosynthesis; D013045:Species Specificity; D013057:Spectrum Analysis
chemical_list: D002734:Chlorophyll
keywords: Chlorophyll fluorescence measurements; Cyanobacteria; Photochemical quenching; Respiration; State transition; Thermal dissipation