title: Partial recovery of light-independent chlorophyll biosynthesis in the chlL-deletion mutant of Synechocystis sp. PCC 6803.
abstract: A chlL-deletion mutant of Synechocystis sp. PCC 6803 designated as chlL- was unable to make significant amounts of chlorophyll in darkness. However, an apparent pseudorevertant has been generated spontaneously that can synthesize an increased amount of chlorophyll under light-activated heterotrophic growth conditions. Under these conditions, the chlorophyll content in this pseudorevertant was about 20% of that in the wild-type strain and about 4 times more than that in the original and in the recently recreated chlL-deletion mutant. This is paralleled by increased performance of dark-grown cells in terms of chlorophyll fluorescence induction and oxygen evolution rates in the pseudorevertant versus in the original mutant. PCR analysis confirmed that the chlL- -pseudorevertant mutant still lacked the chlL gene. These results imply that the light-independent chlorophyll biosynthesis pathway was partly recovered.
authors.affiliation: Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing, PR China. qingyu@tsinghua.edu.cn
authors.forename: Q
authors.initials: Q
authors.lastname: Wu
authors.forename: J
authors.initials: J
authors.lastname: Yu
authors.forename: N
authors.initials: N
authors.lastname: Zhao
mesh_terms: D001426:Bacterial Proteins; D001483:Base Sequence; D002734:Chlorophyll / Q000096:biosynthesis*; D000458:Cyanobacteria / Q000235:genetics* / Q000378:metabolism* / Q000528:radiation effects; D004269:DNA, Bacterial / Q000235:genetics; D017353:Gene Deletion; D005798:Genes, Bacterial; D010788:Photosynthesis; D016133:Polymerase Chain Reaction; D011506:Proteins / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D011506:Proteins; C095441:chlL protein, bacteria; D002734:Chlorophyll