Targeted disruption of the plastid RNA polymerase genes rpoA, B and C1: molecular biology, biochemistry and ultrastructure

作者：Giovanna De Santis‐Maciossek, Waltraud Kofer, Armin Bock, Siegrid Schoch, Rainer M. Maier, Gerhard Wanner, Wolfhart Rüdiger, Hans‐Ulrich Koop, Reinhold G. Herrmann · 发表于：The Plant Journal · 年份：1999 · DOI：10.1046/j.1365-313x.1999.00473.x · 被引用次数：169 · 研究领域：Photosynthetic Processes and Mechanisms、Algal biology and biofuel production、Protist diversity and phylogeny

The plastid encoded RNA polymerase subunit genes rpoA, B and C1 of tobacco were disrupted individually by PEG-mediated plastid transformation. The resulting off-white mutant phenotype is identical for inactivation of the different genes. The mutants pass through a normal ontogenetic cycle including flower formation and production of fertile seeds. Their plastids reveal a poorly developed internal membrane system consisting of large vesicles and, occasionally, flattened membranes, reminiscent of stacked thylakoids. The rpo- material is capable of synthesising pigments and lipids, similar in composition but at lower amounts than the wild-type. Western analysis demonstrates that plastids contain nuclear-coded stroma and thylakoid polypeptides including terminally processed lumenal components of the Sec but not of the DeltapH thylakoid translocation machineries. Components using the latter route accumulate as intermediates. In striking contrast, polypeptides involved in photosynthesis encoded by plastid genes could not be detected by Western analysis, although transcription of plastid genes, including the rrn operon, by the plastid RNA polymerase of nuclear origin is found as expected. Remarkably, ultrastructural, sedimentation and Northern analyses as well as pulse experiments suggest that rpo- plastids contain functional ribosomes. The detection of the plastid-encoded ribosomal protein Rpl2 is consistent with these results. The findings demonstrate that the consequences of rpo ...