title: Changes in photosynthesis and pigmentation in an agp deletion mutant of the cyanobacterium Synechocystis sp.
abstract: The agp gene encoding ADP-glucose pyrophosphorylase is involved in cyanobacterial glycogen synthesis. By in vitro DNA recombination technology, agp deletion mutant (agp-) of cyanobacterium Synechocystis sp. PCC 6803 was constructed. This mutation led to a complete absence of glycogen biosynthesis. As compared with WT (wild type), a 60% decrease in ratio of the c-phycocyanine/chlorophyll a and no significant change in the carotenoid/chlorophyll a were observed in agp- cells. The agp- mutant had 38% less photosynthetic capacity when grown in light over 600 micromol m(-2) s(-1). Under lower light intensity, the final biomass of the mutant strain was only 1.1 times of that of the WT strain under mixotrophic condition after 6 d culture. Under higher light intensity, however, the final biomass of the WT strain under mixotrophic conditions was 3 times that of the mutant strain after 6 d culture and 1.5 times under photoautotrophic conditions. The results indicate that there is a minimum requirement for glycogen synthesis for normal growth and development in cyanobacteria.
authors.affiliation: Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, PR China.
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Miao
authors.forename: Qingyu
authors.initials: Q
authors.lastname: Wu
authors.forename: Guifang
authors.initials: G
authors.lastname: Wu
authors.forename: Nanming
authors.initials: N
authors.lastname: Zhao
mesh_terms: D002338:Carotenoids / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D003001:Cloning, Molecular; D000458:Cyanobacteria / Q000254:growth & development / Q000378:metabolism / Q000502:physiology* / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D051599:Glucose-1-Phosphate Adenylyltransferase; D006003:Glycogen / Q000378:metabolism*; D006706:Homeostasis / Q000502:physiology; D009154:Mutation; D009713:Nucleotidyltransferases / Q000172:deficiency* / Q000235:genetics; D010100:Oxygen / Q000378:metabolism*; D010788:Photosynthesis / Q000502:physiology; D010798:Phycocyanin / Q000378:metabolism; D010860:Pigments, Biological / Q000378:metabolism; D013045:Species Specificity
chemical_list: D010860:Pigments, Biological; D010798:Phycocyanin; D002734:Chlorophyll; D002338:Carotenoids; D006003:Glycogen; D009713:Nucleotidyltransferases; D051599:Glucose-1-Phosphate Adenylyltransferase; D010100:Oxygen; D000077194:Chlorophyll A