MOLECULAR AND FUNCTIONAL CHARACTERIZATION OF A Na~+/H~+ ANTIPORTER OF CYANOBACTERIUM SYNECHOCOCCUS SP PCC 7942

摘要

High salinity is a major environmental factor that affects growth and productivity of higher and microbial plants. Plants alleviate the adverse effects of high salinity first by the active export of Na~-ions by means of primary and secondary mechanisms (Padan et al 1994), and secondly by the synthesis and accumulation of compatible organic osmolytes (Papageorgiou & Murata 1995). Cyanobacteria are used as a model plants in salinity stress studies at the molecular level (a) because, like plants, they perform oxygenic photosynthesis, and (b) as unicellular prokaryotes, their responses to salt stress are more direct. However, their Na~+ transport system and their adaptation to salinity stress are still poorly understood (Inaba et al 2001, Elanskaya et al 2002).