The SALT protein is a 14.5 kDa mannose-binding lectin, originally described as preferentially expressed in rice plant roots in response to NaCl stress. Recombinant SALT lectin was produced in Escherichia coli from a cDNA clone encoding protein. After isopropyl-beta-D-thiogalactopyrano side induction, the expression level achieved was 23% of the soluble protein. The recombinant agglutinin was purified by a single-step process by dialyses against a high concentrated salt solution. After purification, hemagglutination assays of rabbit erythrocytes revealed that the recombinant SALT protein is a potent agglutinin (0.078 mug ml(-1) minimal concentration). The purified recombinant lectin was also used for comparative estimation of native protein amounts in protein extracts from rice plants by Western blot assay. (C) 2003 Elsevier Inc. All rights reserved.