Expression and Ca2+ dependency of plasma membrane K+ channels of tobacco suspension cells adapted to salt stress

The expression of plasma membrane K+ channels of NaCl-adapted tobacco suspension cells and effects of extracellular Ca2+ on plasma membrane K+ channels were investigated. Reverse transcription-PCR (RT-PCR) analysis showed that expression of TORK1, which encodes a K+ channel, was much lower in NaCl-adapted cells than in NaCl-unadapted cells. The magnitude of the outward K+ currents of NaCl-adapted as well as NaCl-unadapted cells decreased with increasing extracellular Ca2+ but there is no significant difference in Ca2+ dependency of the K+ current. These analyses suggest that reduction of the number of K+ channels might cause NaCl adaptation of cells through the decrease of outward K+ currents.