Development requires gene expression to be controlled spatially and temporally, and communication between cells and tissues. Using a forward genetic approach in Arabidopsis, we have identified two critical pathways for normal seedling development. The mRNA decapping complex removes the 7-Me-G cap from mRNAs, initiating 5'-to-3' decay. Two of our mutants (vcs and tdt) have defects in mRNA decapping complex proteins; characterizing these mutants revealed that mRNAs show specificity for particular decay pathways (decapping and exosomal). Current work addresses how mRNAs are targeted to particular decay pathways, and the interaction between developmental signals and decay. Our analysis of the bypass1 mutant revealed that mutant roots produce a novel mobile compound that moves to the shoot and arrests shoot development. The mobile compound appears to be a novel plant hormone. We are working on its identification, and to understand its action in shoots and how the BPS1 protein functions.