Mutlicellular organisms possess tissues containing various cell types. Each cell type differentiates to perform defined functions. We are interested in processes that occur in specific cells. The aim is to identify mechanisms allowing differential gene expression in particular cells, and the consequences of this differential expression in those cells. For example, Applicant 1 aims to identify differences in methylation of promoter elements between cell-types, applicants 3-5 wish to determine transcript abundance from specific cell-types, and then use that information to generate developmental and circadian networks, or understand responses to pathogen attack or cell signalling. As few as ten plant cells have been collected via LCM prior to analysis of gene expression, and so all the work proposed is feasible and we should make significant advances in each of our fields.