Abstract
PsbP is an extrinsic protein that is associated with photosystem II (PSII) core at the luminal side in higher plants and green algae. In our laboratory, tobacco plant in which PsbP was downregulated by RNAi was produced (ΔPsbP). In ΔPsbP tobacco, Fv/Fm value was severely decreased, whereas most of PSII subunits were accumulated. In addition, the amount of photosystem I was markedly decreased, while the amount of the subunits of NDH and Cyt b6/f complex were increased. These observations were not found in Chlamydomonas mutant lacking PsbP and suggest that knockdown of PsbP could cause the large effect on the property of the photosynthetic electron transfer in higher plants. In this report, further analysis on ΔPsbP plant using the chlorophyll fluorescence and thermoluminescence will be described. Effects of the PsbP knockdown on the gene expression and on the protein-complex formation in the thylakoid membranes will be also reported.
