Abstract
We screened a rice full-length cDNA library for novel cation transporters involved in the salt-tolerance. As a result, the Shaker family K+ channel OsKAT1 was found to be a suppressor of the salt-sensitive phenotype of mutant yeast. OsKAT1 also suppressed a K+ transport-defective phenotype of another mutant, indicating the function of OsKAT1 in K+ uptake. Under salt stress conditions, cellular Na+ was decreased in OsKAT1-expressing yeast following the increase of K+. The improvement of salt-tolerance and the increase of cellular K+ were observed also in rice cells overexpressing OsKAT1, suggesting OsKAT1 may participate in maintenance of cytosolic cation homeostasis during salt stress and protect the cells from Na+. The expression of OsKat1 was restricted to internode and rachis of wild type plant while other Shaker family genes were expressed in various organs. OsKAT1 may be involved in salt-tolerance of rice plant cooperatively with other K+ channels.
