Abstract
The expression of the isiAB operon, which encodes CP43' and flavodoxin, is induced under heat or oxidative stress conditions as well as iron deficient conditions. The aim of this study is to elucidate their roles for acquisition of stress tolerance with using isiA/isiB and isiB disruptants of Synechocystis sp. PCC 6803. Both mutants were more sensitive to oxidative or heat stress than wild type, suggesting that they play roles in the protection from these stresses. To our surprise, the isiB mutant was more sensitive to methylviologen (5 μM) than the isiA/isiB mutant, while the isiA/isiB mutant was more susceptible to heat stress than the isiB mutant. These results indicate that CP43' and flavodoxin play roles under oxidative and heat stress conditions.
