Figure 2.
Knockdown of CAS Leads to Light Sensitivity and to Decreased NPQ Induction and LHCSR3 Expression.
(A) Quantification of CAS amounts in thylakoids isolated from the wild type (WT; cw15-arg7) and amiRNA-cas-27. Cells were grown in TAP under LL upon SDS-PAGE fractionation and immunoblot analysis (100% equals 4 μg of chlorophyll per lane; CF1 served as the loading control).
(B) Quantification of PSI and PSII subunits in the wild type (cw15-arg7) and amiRNA-cas-27 grown in TAP under LL. Four micrograms of chlorophyll of whole-cell extracts was fractionated on a 13% SDS-PAGE, and several protein abundance were analyzed by immunoblots. PSI-related proteins: PSAD, LHCA3, LHCA9, and PGRL1; PSII-related proteins: PSBA and LHCBM6; loading control: CF1.
(C) Growth phenotype of the wild type (cw15-arg7) and cas-kd strain amiRNA-cas-27 after 18 h under HL. Cells were grown in 80% HSM containing the indicated amount of Ca2+ in the form of its chloride salt. Starting cell density of the cultures was 1 × 106 cells/mL. The picture shows the bottom of Erlenmeyer flasks containing the cell cultures.
(D) Irradiance dependence of quantum yield of PSII (YII) and of NPQ in the wild type (cw15arg7) and amiRNA-cas-27. Cells were grown in TAP under LL and then exposed for 2 h under HL in 80% HSM. Values plotted are the means of three samples ± sd.
(E) Quantification of LHCSR3 amounts in the wild type (cw15-arg7) and amiRNA-cas-27. Cells were grown in TAP under LL and then shifted for 2 h to HL (200 μE m−2 s−1) in 80% HSM containing 0.34 or 3.06 mM CaCl2 concentration. Five micrograms of chlorophyll of whole-cell extracts was fractionated on a 13% SDS-PAGE, and LHCSR3 abundance was analyzed by immunoblots. CF1 signal served as a loading control.