NaCl-induced photoinhibition and recovery of the photosynthetic activity of a katG − mutant of cyanobacterium Synechocystis sp. PCC 6803

Abstract

The joint effects of 0.5 M NaCI and light of different intensities on the activity of the photosynthetic apparatus and ATP contents in cells of the katG- mutant of cyanobacterium Synechocystis sp. PCC 6803 have been studied. The mutant demonstrated a higher photoinhibition rate and a slower rate of recovery compared to the wild type, as it was shown by measurements of the CO2-dependent O2 production and delayed light emission of Chl a. The presence of 0.5 M NaCl in incubation medium induced the equal photoinhibition of the photosynthetic apparatus at I = 1200 microE m(-2) x (-1) in the mutant and wild-type cells. At I = 2400 microE m(-2) x c(-1), a stronger inhibition and a slower recovery of the photosynthetic apparatus activity in the kat- mutant than in wild-type cells was observed. The data obtained evidence an important role of catalase-peroxidase in the system of reparation of the photosynthetic apparatus damaged by high-intensty light, especially against the background of NaCI stress.