The effect of pds gene silencing on chloroplast pigment composition, thylakoid membrane structure and photosynthesis efficiency in tobacco plants

Nicotiana tabacum plants that are silenced in pds gene have been constructed by RNAi technology. Transgenics showed different degrees of albinism and PSII efficiency was decreased significantly compared to wild type plants. The total carotenoid contents decreased. The ratio of chlorophyll (Chl) a to b was unchanged while the content of both declined. The grana stacking of thylakoid in variegation part was as normal as in the control and etioplast occurred in the white sector of leaf. The concentration of thylakoid membrane protein of molecular weight about 20 kDa was significantly increased compared to wild type plants according to the same contents of Chl. These observations suggest the exact matching of pigments and proteins is important for energy absorption and transfer in photosynthesis and mismatching of them could cause malfunction of PSII.