Abstract
The psbP gene family encoding the extrinsic 23-kDa proteins in the oxygen-evolving complex of photosystem II consists of four isogenes in Nicotiana tabacum. Tobacco psbP genes are divided into two groups (minor group-I; 1A and 5B: major group-II; 2AF and 3F) by the sequence similarity. We have analyzed the physiological function of these psbP genes using group-specific PsbP-silenced transgenic tobacco plants obtained by RNA interference (see Yamamoto et al., JSPP Annual Meeting 2004).
Preliminary analyses in T0 and T1 transgenic plants using a PAM fluorometer showed significantly higher F0 and the decreased photosynthetic electron transport rate in group-II-specific PsbP-silenced tobacco than that in control tobacco, whereas group-I-specific PsbP-silenced tobacco was indistinguishable from control tobacco. These results suggest the difference in the function or in the level of expression between the two groups of psbP. Further characterization with T2 plants is currently under way.
