Abstract
In higher plants, cross-talk between the nucleus and plastids is one of the most important intracellular communications. Plastid-to-nucleus retrograde signaling coordinates the nuclear gene expression in response to functional state of chloroplasts. To date, several retrograde signals have been reported, but little is known about their signaling pathways. To investigate the signaling mechanism from plastids to the nucleus, we used the Arabidopsis mutant, ppi2, which lacks the protein import receptor Toc159. We examined the effect of norflurazon on the expression of nucleus-encoded chloroplast proteins involved in retrograde signaling using wild type and ppi2 mutant. The results indicate that the expression of some genes is affected by norflurazon treatment. We also examined genetic interactions between ppi2 and mutations involved in plastid signaling. On the basis of these results, we will discuss the signaling pathway from plastids to the nucleus.
