Cloning and Differential Gene Expression of Two Catalases in Suaeda salsa in Response to Salt Stress

摘要

Two different cDNA clones (Sscatl and Sscat2) encoding catalase, the primary important H_2O_2-scavenging enzyme, were isolated from a λZap-cDNA library constructed from a 400 mmol/L NaCl-treated library of Suaeda salsa (L.) Pall aerial tissue. Sscatl (1.7 kb) contains a full open reading frame of 492 amino acids and Sscat2 (1.1 kb) is a partial clone. BLAST analysis indicates that the two clones share 71.9% identity in nucleotide sequence and 75% identity in deduced amino acid sequence within the last 287 amino acid residues of Sscatl. Southern blotting analysis showed that Sscatl is multicopy in S. salsa genome, while Sscat2 is a single copy gene. Northern blotting analysis showed a rapid increase in the steady-level of both genes in roots after 48 h salt treatment, but only Sscatl was induced in salinity treated leaves. Time-course analysis carried out in leaves confirmed that Sscatl was induced by salt stress, in contrast to Sscat2 . These implied that the expression of Sscatl and Sscat2 genes are differentially regulated in S. salsa . The activity of total catalase is dramatically increased in response to salt stress.