Ammonium tolerance in the cyanobacterium Synechocystis sp. strain PCC 6803 and the role of the psbA multigene family

摘要: Ammonium is one of the major nutrients for plants, and a ubiquitous intermediate in plant metabolism, but it also known to be toxic many organisms, particular plants oxygenic photosynthetic microorganisms. Although previous studies revealed link between ammonium toxicity photodamage cyanobacteria under vivo conditions, ammonium-induced photosystem II (PSII) has not yet been investigated with isolated thylakoid membranes. We show here that directly accelerated PSII Synechocystis sp. strain PCC6803, rather than affecting repair photodamaged PSII. Using membranes, could demonstrated primarily occurred at oxygen evolution complex, which binding site ammonium. Wild-type Synechocystis PCC6803 cells can tolerate relatively high concentrations because efficient repair. tolerance requires all three psbA genes since mutants any single are more sensitive wild-type cells. Even poorly expressed psbA1 gene, whose expression was studied some detail, plays detectable role tolerance.