Font Size: a A A

Cloning And Differential Gene Expression Of SsAPX, SsCAt1 And SsCAT2 In Suaeda Salsa In Response To Salt Stress

Posted on:2003-09-30Degree:MasterType:Thesis
Country:ChinaCandidate:C L MaFull Text:PDF
GTID:2120360062495915Subject:Developmental Biology
Abstract/Summary:PDF Full Text Request
Suaeda salsa is a leaf succulent euhalophyte that may have evolved the unique salt-tolerance mechanism. The results of most studies suggest that plant salt tolerance is usually correlated with a more efficient antioxidant system. And there may have distinct difference on the scavenging of reactive oxygen species (ROS) between euhalophyte and glycophyte. So cloning those genes that encoding enzymes engaged in scavenging ROS from S. salsa may attribute to get insight into the mechanism of plant salt tolerance.Three different cDNA clones (SsAPX, SsCATl and SsCAT2), the primary important H2O2 enzymes, were isolated from a A. Zap-cDNA library constructed from a 400 mmol/L NaCl-treated library of Suaeda salsa aerial tissue. Then they were analyzed by sequence characterization, genomic organization and the differential expression in response to salt stress. SsAPX encode a cytosol ascorbate peroxidase. It is a single copy gene in S.salsa genome. While the expression of APX was slightly induced by salt stress, the activity of SsAPXincreased significantly in response to salt stress. SsCATl and SsCAT2 encode catalases, whichlocated in Suaeda salsa peroxisome. SsCATl has at least two copies and SsCAT2 has only one copy in the Suaeda salsa genome. Northern blot analysis showed a rapid increase in the steady-level of both genes in roots after 48h 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 SsCATl and SsCAT2 genes are differentially regulated in S. salsa in response to salt stress. The activity of total catalase isdramatically increased in response to salt stress. All the results indicated that SsAPX, SsCATl and SsCAT2 might play an important role in protecting Suaeda salsa from the oxidation damage...
Keywords/Search Tags:euhalophyte, salt stress, suaeda salsa, ascorbate peroxidase, catalase
PDF Full Text Request
Related items