Abstract
By means of in vitro reconstitution with spinach PS II particle, we previously found that a small subunit protein, PsbL in PS II complex is involved in the primary electron transfer at the donor side of P680 at pH lower than 5.5. In this study, using a reverse genetic approach, we have inactivated the psbL gene in the tobacco chloroplast genome to investigate the function of PsbL in vivo.
The homoplasmic psbL knockout plants (ΔpsbL) could grow on sucrose containing medium, but it displayed a clear mutant phenotype. While young leaves were normally green, older were almost completely white. The PSII activity of ΔpsbL determined by chlorophyll fluorescence at room temperature with PAM was about 10% of the wild type plant, irrespective of young or old leaves. The function of PsbL in the PSII will be discussed in the combination of the in vitro and in vivo data.
