Plastid Transcription: Competition, Regulation and Promotion by Plastid- and Nuclear-Encoded Polymerases

Abstract

Complete plastid function, including gene expression, is necessary for photosynthesis. Furthermore, plastid genomes have been retained in non-photosynthetic plants (Wolfe et al., 1992) and even in the distantly related Apicomplexans (Wilson et al., 2003; see Chapter 24), which suggests that they have key functions outside of photosynthesis. Recently published reverse genetic experiments from Arabidopsis and tobacco (Ahlert et al., 2003; Kuroda and Maliga, 2003; Yao et al., 2003) provided the first direct evidence that plastid-encoded or plastid-localized proteins are necessary for embryogenic tissues to grow or develop.