title: Salt stress inhibits the repair of photodamaged photosystem II by suppressing the transcription and translation of psbA genes in synechocystis.
abstract: Light stress and salt stress are major environmental factors that limit the efficiency of photosynthesis. However, we have found that the effects of light and salt stress on photosystem II (PSII) in the cyanobacterium Synechocystis sp. PCC 6803 are completely different. Strong light induced photodamage to PSII, whereas salt stress inhibited the repair of the photodamaged PSII and did not accelerate damage to PSII directly. The combination of light and salt stress appeared to inactivate PSII very rapidly as a consequence of their synergistic effects. Radioactive labeling of cells revealed that salt stress inhibited the synthesis of proteins de novo and, in particular, the synthesis of the D1 protein. Northern- and western-blotting analyses demonstrated that salt stress inhibited the transcription and the translation of psbA genes, which encode D1 protein. DNA microarray analysis indicated that the light-induced expression of various genes was suppressed by salt stress. Thus, our results suggest that salt stress inhibits the repair of PSII via suppression of the activities of the transcriptional and translational machinery.
authors.affiliation: Department of Regulation Biology, National Institute for Basic Biology, Myodaiji, Okazaki 444-8585, Japan.
authors.forename: Suleyman I
authors.initials: SI
authors.lastname: Allakhverdiev
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Nishiyama
authors.forename: Sachio
authors.initials: S
authors.lastname: Miyairi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Noritoshi
authors.initials: N
authors.lastname: Inagaki
authors.forename: Yu
authors.initials: Y
authors.lastname: Kanesaki
authors.forename: Norio
authors.initials: N
authors.lastname: Murata
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D001426:Bacterial Proteins / Q000235:genetics; D002734:Chlorophyll / Q000037:antagonists & inhibitors / Q000235:genetics; D000458:Cyanobacteria / Q000187:drug effects* / Q000235:genetics / Q000528:radiation effects; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects / Q000528:radiation effects; D008027:Light; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics*; D045332:Photosystem II Protein Complex; D014176:Protein Biosynthesis / Q000187:drug effects / Q000235:genetics; D012965:Sodium Chloride / Q000494:pharmacology*; D014157:Transcription Factors / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D014157:Transcription Factors; C422369:photosystem II, psbA subunit; D002734:Chlorophyll; D012965:Sodium Chloride