The cold-induced switch in direction of chloroplast relocation occurs independently of changes in endogenous phototropin levels
Fig 5
Increased Mpphot expression is not required for the induction of the cold-avoidance response.
(A) Immunoblot analysis of endogenous Mpphot in 4-day-old WT gemmalings (white light for 3 days and BL25 for 24 h at 22°C), incubated under BL25 for 0 h (22°C), and 3 h, 6 h and 9 h at 5°C. Histone H3 protein is shown as a loading control. (B) Representative chlorophyll fluorescence images of WT gemmalings incubated under the same light and temperature conditions as shown in (A). (C) P/A ratios calculated from chlorophyll fluorescence images after incubation for 0 h (22°C), and 3 h, 6 h and 9 h at 5°C. Error bars indicate standard deviations. (D) Immunoblot analysis of activity of CaMV35S promoter in M. polymorpha under cold conditions. A transformant expressing Citrine under the control of CaMV35S promoter (35S::Citrine/WT) was used. Coomassie Brilliant Blue (CBB)-stained Rubisco large subunit (RBCL) was used as a loading control. (E) Chlorophyll fluorescence images showing the cold-avoidance response in complementation lines (35S::Mpphot-Citrine/MpphotKO). After incubation under BL25 at 22°C, the gemmalings were transferred to 5°C under the same light conditions.