Exogenously applied hydrogen peroxide modifies the course of the Chlamydomonas reinhardtii cell cycle.

The interaction of NO and HO in the regulation of plant development is well documented. We have recently shown that the content of NO and HO changes in a characteristic way during the cell cycle of Chlamydomonas reinhardtii (Pokora et al., 2017), which implies participation of these molecules in the regulation of Chlamydomonas development. To verify this assumption, HO was supplied at a concentration about 1.5 times higher than that determined in the control cells. Cells were synchronized by alternating the light/dark (10/14 h) regimen. HO was added to zoospore suspensions, previously held in the dark, and cells growing for 3, 6, and 9 h in the light. The data indicate that, depending on the phase of the Chlamydomonas cell cycle, HO, via mild modification of redox homeostasis, may: a) accelerate or delay the duration of the cell cycle; b) increase the number of replication rounds occurring in one cell cycle; c) modify the biomass and cell volume of progeny cells and d) accelerate the liberation of daughter cells. This provides a tool to control the development of Chlamydomonas cell and thus offers the opportunity to obtain a population of cells with characteristics desired in biotechnology.