Abstract
Active oxygen species (AOS) are important signal molecules that regulate many cellular processes, including environmental stress response. We have previously investigated that cytosolic APX-suppressed tobacco BY-2 cell lines (cAPX-S1) show sustained cellular AOS accumulation and increased tolerance against diverse environmental stresses, such as heat and salinity. The aim of this study is to explore the redox-responsible genes together with the redox signaling pathway, which afford the increased stress tolerance. In-gel kinase assay using the myelin basic protein as a phosphorylating substrate showed that the activation of the predominant 36 and 46 kDa kinases occurs in cAPX-S1 cells, but not in wild-type cells. By suppressive subtraction analysis, total seven upregulated genes were isolated in cAPX-S1 cells. Among them, we identified three genes as Hsp70, DnaJ-like protein, and purple acid phosphatase, which are known to be involved in heat or salt stress-responsible genes.
