%0 Journal Article %T Co-option of EDM2 to distinct regulatory modules in Arabidopsis thaliana development %A Tokuji Tsuchiya %A Thomas Eulgem %J BMC Plant Biology %D 2010 %I BioMed Central %R 10.1186/1471-2229-10-203 %X Here we report that EDM2 affects additional developmental processes which include the formation of leaf pavement cells and leaf expansion as well as the development of morphological features related to vegetative phase change. EDM2 has a promoting effect of each of these processes. While WNK8 seems not to exhibit any vegetative phase change-related function, it has a promoting effect on the development of leaf pavement cells and leaf expansion. Microarray data further support regulatory interactions between WNK8 and EDM2. The fact that the effects of EDM2 and WNK8 on leaf pavement cell formation and leaf expansion are co-directional, while WNK8 counteracts the promoting effect of EDM2 on floral transition, is surprising and suggests that WNK8 can modulate the activity of EDM2.We propose that EDM2 has been co-opted to distinct regulatory modules controlling a set of different processes in plant immunity and development. WNK8 appears to modulate some functions of EDM2.The defense regulator EDM (Enhanced Downy Mildew) 2 was previously shown in Col (Columbia) accessions of Arabidopsis thaliana (Arabidopsis) to be specifically required for immunity mediated by the disease resistance (R)-gene RPP (Resistance to Peronospora parasitica) 7 against the Hiks1 isolate of the pathogenic oomycete Hyaloperonospora arabidopsidis (formerly Peronospora parasitica; Hpa) [1]. Unlike many other plant defense mechanisms RPP7-mediated immunity is independent from the defense hormone salicylic acid. Furthermore, RPP7-mediated immunity appears thus far to be the only defense mechanism that EDM2 is involved in, as no other EDM2-dependent R-gene functions have been reported yet. EDM2 also does not contribute to basal defense, a weaker non-specific plant immune response [2]. Thus, the role of EDM2 in plant defense seems to be restricted to a single or a limited number of defense pathways. The EDM2 protein is nuclear-localized and bears typical features of transcription factors and epigenetic r %U http://www.biomedcentral.com/1471-2229/10/203