Abstract
A large gene family encoding proteins with pentatricopeptide repeat (PPR) motif consisting of 35 degenerate amino acids exists in flowering plants but not in algae, fungi, or animals. For instance, the Arabidopsis thaliana genome has 470 PPR protein genes and the rice (Oryza sativa) genome encodes 670 PPR proteins. In contrast, the moss Physcomitrella patens genome is estimated to encode 70 to 100 PPR proteins. The most interesting feature of the plant PPR proteins is their cellular localization; 80% of Arabidopsis PPR proteins are predicted to localize in either the mitochondria or plastids. To investigate the function of plastid PPR proteins, we have generated and characterized the plastid-localized PPR protein gene disruptant of P. patens, and characterized the Arabidopsis T-DNA mutants with insertion in PPR protein genes. PPR513-11 disruptant mosses displayed abnormal phenotypic characters such as the growth of protonema colonies, the number and shape of chloroplasts, and so on.
