Abstract
Transcriptomic analyses of the Synechocystis sp. PCC 6803 reveal that the expression of various genes for functionally uncharacterized proteins are up-regulated under environmental stress conditions. In this study, we focused on slr1674 gene, of which expression is drastically induced under the stresses, and its paraloge, slr1638. The expression of slr1674 gene was transiently induced under salt and oxidative stresses, whilst slr1638 gene was expressed constitutively. Each disruptant of slr1674 or slr1638 genes showed longer lag phase than wild-type strain, suggesting that the mutations might affect the ability of cells to protect fromexcess light stress at the initial growth phase after the dilution of culture. To confirm this hypothesis, we examined recovery rate of each disruptants from the photoinhibition. The recovery rates in the mutants were much slower than that in wild-type cells. These results suggested that these proteins might be involved in the recovery process from photoinhibition.
