A ROLE FOR CHLOROPHYLL PRECURSORS IN PLASTID-TO-NUCLEUS SIGNALING

Abstract

Initiative, 2001). As expected, the nucleus plays a dominant role in chloroplast development, but the expression of nuclear genes that encode chloroplast proteins is also dependent on the functional and developmental state of the plastid. Plastids send signals to the nucleus that are essential for proper expression of nuclear genes that encode proteins with functions related to photosynthesis, coordinating expression of chloroplast and nuclear genomes, and proper leaf morphogenesis (Rodermel, 2001; Surpin et al., 2002; Rodermel and Park, 2003; Gray et al., 2003). Because plastids perform essential metabolic and biosynthetic functions, it is not surprising that the functional state of the plastid has a dramatic influence on gene expression and developmental decisions, but little is known about the molecular mechanisms that plastids use to communicate with other cellular compartments. Mayfield and Taylor (1984) used maize seedlings in which chloroplast development was arrested at an early developmental stage to provide the first evidence that the developmental state of the plastid has a powerful effect on the expression of nuclear genes that encode particular chloroplast proteins. Subsequently, a number of studies have indicated that proper expression of nuclear genes that encode proteins with functions related to photosynthesis is dependent on normal chloroplast development in diverse monocotyledonous and dicotyledonous genome was lost or transferred to the nucleus of the eukaryotic host (Herrmann