The Dawdle (DDL) gene in Arabidopsis encodes a protein with a Fork Head-Associated domain. A mutation in the DDL gene causes pleiotropic phenotypes and reduced the levels of several microRNAs. However, it is not completely known whether the FHA domain of the DDL is necessary for its function. Furthermore, the interactors involved in the same signaling pathway as DDL have not been identified yet. To determine the role of FHA domain in DDL function, four Tiller mutant lines were isolated and characterized. Results from phenotypic characterization suggest that the FHA domain may require for DDL function. For interactors, the interactions between DDL and At1G68010, At2G28200, At3G68010 and At4G18372 were identified by Yeast Two Hybrid, and then confirmed by the Split Luciferase assays. In addition, T-DNA mutants for each interactor were isolated and analyzed phenotypically suggesting that the genes carrying those T-DNAs should function in the same signaling pathway as DDL.